It looks like you did a pretty nice job on it. The camo looks good, especially for your first free-hand camo. There are a few things still at issue with your model though
First, the camo is not USMC pattern, but the standard 3-tone NATO camo pattern used on just about all US vehicles since the mid-'80s.
Secondly, your tank has Army six-shot smoke launchers USMC tanks have 8-shot smoke launchers specific to USMC Abrams.
The internal surface of the hatches should still be green, they have not been white on US tanks since before WWII. The interior of the tank is a semi-gloss white, but not the insides of the hatches. It also looks like you still need to paint the periscopes on the CWS.
Lastly, this statement isn't accurate...
"absence of the missile countermeasures device (standard on USMC tanks) isn't presence."
The MCD was only used on USMC tanks in the initial invasion of Iraq in '03. They are not standard on USMC Abrams and only used when there is a threat from optically-guided anti-tank missiles. So no worries there.
As your tank is now, it is an early '90s US Army M1A1 Abrams due to the smoke grenade launchers.
Here is a similar time period USMC M1A1 Abrams.
Gino P. Quintiliani - Field Artillery - The KING of BATTLE!!!
Check out my Gallery: https://app.photobucket.com/u/HeavyArty
"People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf." -- George Orwell