I don't think anyone here is suggesting that you are dishonest . All the options look as if they have been there from day one . However, we don't know for sure on some of them, and neither do you.. Obviously the leather interior, overhead console, and small back glass and SE emblems, with carpet and reflector at bottom of door panel are all part of the SE package , and being the VIN is there and clearly states JS29U0..and since you told us the cowl and rad support numbers are still on the car, we know the car is an SE by the 29 , so we know those items are correct . But what we do not know is weather someone added the cruise control in 1975 , we don't know if the car was an AM 8track or An AM FM (we can eliminate AM of course), we can't say for sure that it is a power window car or if someone swapped the door panels and added power windows in 1979 from a wrecked 318 challenger they found in the local salvage yard. Chances are 99% all that stuff is factory correct to this car , but with no tag or sheet or window sticker, who can say for certain. You best bet is to do what you have already done, which is to photo document the car in it's unrestored state
and is really all you can do . A repro tag would just contain some guesswork and incorrect numbers such as VON , so just hang up the idea of a repro tag . You knew when you bought it there was no tag , and you know that is about a 25 % hit on the value of the car , give or take, and you know an FC7 R/T SE U code Challenger is an "investment car" . You may not be planning on making a profit, but I would bet you also are not planning on being buried in this car either , so , the rarity and value of the car is certainly a factor . One would hope you negotiated the purchase well and took the missing tag in as a major factor when calculating your purchase price of this car . I would personally photo every inch of the car , then restore the car as you see in the pics . That's really the best you can do. You will have a beautiful car when it is done . Any U code R/T SE is a rare and desirable car . It's a car any true Mopar fan would be proud to own, tag or no tag.

Greg