I would search for B-17 serial numbers, instead of the just that one serial. You might find it in a group of serials, i.e. 4183869 - 4184958. I've used this and found several sites listing all the serial numbers used on B-17s. If the aircraft is fake, might as well add a colorful nose art to it, and at least get the BG/BS marking right. I did that on my last B-17. I created a fake serial number and nost art/name, but made the squadron markings from a real BG/BS.
How many numbers of the serial number displayed on the tail depended on the individual BG/BS. The serial numbers where assigned by the government so wheather is was built by Boeing (BO), Vega (VE), or Douglas (DL) didn't matter. Most BG left off the first 4 in the serial (serials started with a 4, follwed by 1, 2, 3, or 4 depending on what year the funds for the aircraft was approved. So lets take the serial number of the Memphis Belle, 41-24485. 41 indicates that the funds for the aircraft where approved in 1941, even though the aircraft it self wasn't delivered to the USAAF till 1942. 24485 was a number inside a block of numbers for the number of B-17s approved for that budget, i.e. 10 B-17s where assigned so 41-24480 to 41-24490 was given to Boeing for 10 B-17s, while 41-24491 to whatever could be assigned to B-25s.
Same thing goes to the squadron codes and aircraft letter. Most BGs put the squadron and aircraft code on the fuselodge, with the aircraft code repeated on the tail (late in the war, when the high visibilty markings where mandated). In the early part of the war, squadron and aircraft codes where just on the fuselodge). Some BG used strips of color to identify squadron, with the aircraft code only on the tail. Again, it depended on the on the BG.
Not all B-17s had nose art. They where few and far between, but there where some with no nose art, especially late in the war when no particular aircraft was assigned to a crew. I.E. aircraft with serial number 42-89765 was assigned to crew A on Monday, crew B on Tuesday,, Crew C flew in her on Thursday, with crew A flying a mission in her on Saturday.
Speaking of the 96th BG, the following is a picture from the book "Battle Colors, Volume 1" Sorry don't have a scanner, so I took a picture of the page with the markings. Replace the red you see in the pic with the right color for the BD you're portraying. The 337th BS used red, 338th used yellow, and 339th used blue. the 413 BS was a pathfinder unit, so no color was used. In this BG, the aircraft code was repeated on the tail.
Hope this helps.