What is the difference

I am assuming you mean the second Helldiver, not the early biplane one.  The WW2 Helldiver is quite a bit bigger than the SBD, built around a much bigger engine.  Thus heavier, bulkier looking.  Since the Helldiver joined the fleet in the middle of the war it is also reasonable to think that some of them were in the late dark gloss blue overall.

The Dauntless is the one I was  not sure of the right shade of blue.

The Dauntless wore a few different schemes, so it depends on the aircraft you're building and when it was operational.

Early in the war, the color scheme was blue-gray over light gray. Dauntlesses operating at Coral Sea, Midway, Guadalcanal, etc wore this scheme. If you've got just the circled star insignia, not the stars-and-bars, it wore this.

Mid-war, the Navy adopted tri-color camoflage of white undersides, intermediate blue on the horizontal surfaces (fuselage, basically) and non-specular sea blue on top. Later-war Dauntlesses wore this scheme. I don't think any ever adopted the switch to all sea blue.

There's also the gray/gray Atlantic scheme.

The model is a Monogram from the 1960's the instructions for the colors are real basic like blue or brown not much more than that. With the newer models they give FS numbers so I can get the color dead on.

Here's a  link to a Google page of SBD images. You'll note, it also wore interwar yellow wings with natural metal fuselage.

The Douglas SBD wore all US Navy camouflages, including the overall glossy Dark Sea Blue (FS 15042), and also wore the USAAF Olive Drab over Neutral Grey as the A-24 Banshee, as did the the Curtiss SB2-C as the A-25 Shrike..

The Mongram SBD is an SBD-4, I think..

Basically, you need to decide "when" you're modeling your SBD...

Battle of Coral Sea-era

http://www.modellversium.de/galerie/img/2/5/5/2255/30501/douglas-sbd-3-dauntless-hasegawa.jpg

My personal favorite is the three-color variant, Non-Specular Sea Blue / Intermediate Blue / White with the short-lived red-bordered US Star & bars (July-Sep 1943)...

http://dw.squawk1200.net/app/webroot/tiny_files/images/SBD/DW_Planes_SBD.jpg

http://www.aviation-history.com/douglas/sbd-6a.jpg

Battle of Midway-era:

http://img.wp.scn.ru/camms/ar/766/pics/3_8.jpg

Special markings for "Operation Torch", landings on N. Africa, Nov 1942

http://img.wp.scn.ru/camms/ar/766/pics/3_24.jpg

 The Atlantic scheme of Dark grey over white is also an eye-grabber, as Doog's photo shows..

http://www.hyperscale.com/galleries/2002/sbd5rf_2.htm

http://i1-games.softpedia-static.com/screenshots/9-1095_1.jpg

1944-post-war

http://www.warbirdalley.com/sbd.htm

USAAF A-24 Paint-scheme

http://en.wikipedia.org/wiki/File:Side_View_of_U.S._Army_A-24_Banshee,_National_Museum_of_the_USAF.jpg

Visually, the A-24 differed from the SBD only in that it had the arresting hook removed, and a larger, pneumatic tail-wheel instead of the small, hrad-rubber carrier-type tailwheel..

 USAAF A-25 Shrike

http://www.aviationartstore.com/images/Print_A-25_web.jpg

You might find this article of interest as well, if you're a Monogram fan..

http://www.aircraftresourcecenter.com/Gal5/4101-4200/gal4123_Dauntless_Stanley/00.shtm

Hans von Hammer

USAAF Olive Drab over Neutral Grey ...... as did the the Curtiss SB2-C as the A-25 Shrike..

 

I've got an idea!!!

Already had plans to do my SBD as an A-24, wasn't aware of the 25.

Is there much difference between the SB2-C / A-25? (aside from paint) The rear fuse/lower tail looks different in that last link.

The biggest difference in the A-25/SB2C is gonna be the tail wheel. The A-25 should have a pneumatic tail wheel as opposed to the solid rubber tail wheel used on carrier aircraft. Most likely the tail hook should be removed as well.

fermis

Hans von Hammer:

USAAF Olive Drab over Neutral Grey ...... as did the the Curtiss SB2-C as the A-25 Shrike..

 

I've got an idea!!!

Already had plans to do my SBD as an A-24, wasn't aware of the 25.

Is there much difference between the SB2-C / A-25? (aside from paint) The rear fuse/lower tail looks different in that last link.

What Stik said.. But the profile pic seems to have a little issue with the turtleback, yeah..

Check this pic of the A-25A..

http://upload.wikimedia.org/wikipedia/en/5/55/USAF_Curtis_A-25A-5-CS_Shrike_in_flight,_Serial_Number_41-187187.jpg

And here's a whole slew of 'em..

http://www.google.com/search?tbm=isch&hl=en&source=hp&q=A-25+Shrike&gbv=2&oq=A-25+Shrike&aq=f&aqi=g1&aql=&gs_l=img.12..0.1422l4547l0l5891l11l11l0l3l3l0l282l1424l0j2j4l6l0.frgbld.

Hans von Hammer

Check this pic of the A-25A..

http://upload.wikimedia.org/wikipedia/en/5/55/USAF_Curtis_A-25A-5-CS_Shrike_in_flight,_Serial_Number_41-187187.jpg

And here's a whole slew of 'em..

http://www.google.com/search?tbm=isch&hl=en&source=hp&q=A-25+Shrike&gbv=2&oq=A-25+Shrike&aq=f&aqi=g1&aql=&gs_l=img.12..0.1422l4547l0l5891l11l11l0l3l3l0l282l1424l0j2j4l6l0.frgbld.

Gah! More ammo to my belief that every plane looks better in Navy blues. The A-24 is similarly dumpy and hideous (and I love the Dauntless), while the navalized bombers (PBJ, PB4Y, PV-1, etc) all look much sharper than their OD/NG counterparts, at least to my eyes.

Kinda makes me want to build a P-47 in tri-color, just to see.