Lovely work John.
Daniel - early J's had the earlier muffler rather than the two exhaust pipes, making it even harder to distinguish between the two. One key distinction is the rear idler wheel, the lack of the gadget at the rear for the turret traverse (hand only for the J) and the spare tracks on the side in place of the air filter pod on the right fender. Strictly-speaking, John has not got the pipes upside down because that is precisely what the Revell instructions tell you to do! They should, of course, be the other way up, but it's hardly John's fault if the instructions are wrong in the first place.