Centaur567
From what I undarstand, I depends on the model of UH-1 your asking about. The D model had an oil pan bulge behind the rear skid. This was removed and replaced by a cut out for the oil cooler fan with a screen on the H model. The photo above of the orange and white huey is an H model. Gary
You are incorrect on the oil cooler bulge on early UH-1Ds. All long-bodied Hueys (UH-1D/H/N) had/have rectangular cut-out with the oil cooler tucked up inside the fuselage.
Here is a Vietnam-era UH-1D/H showing the cut-out with the oil cooler inside.
and a more modern UH-1H showing the cut-out.
The square bulge was present on short-boadied UH-1B/C models and did contain the oil cooler, which stood proud of the fuselage due to a space issue.
UH-1B/C w/oil cooler bulge. You can just make out the bulge in the below pics.
The issue with most UH-1D/H kits still having the bulge comes from the original Revell UH-1D kit from the late '60s which incorrectly had the bulge and all other companies copied that feature. If you are building a long-bodied Huey, the bulge should be removed and replaced by the cut-out.
Additionally, the orange and white helo above is actually a twin-engine UH-1N, which also has the opening for the oil cooler. Not sure what type your video game Huey in your pic is supposed to be since the US Military never used that gun configuration. Aussie UH-1D/H Bushrangers did use the forward miniguns and rear M60s though.