That's not what I meant. Sorry if I wasn't clear. It's just one of many suggestions and/or possibilities and doesn't hurt to look if you suspect the tail panel is original, I've seen some hack jobs. Most cases you can tell if the spot welds have been tampered with, but the majority of clones I've seen, no one wants to go through the trouble to change the whole panel, hence the back yard whiz wheel holes.
Many other things to look at, however, there really isn't any sure fire way to determine RS status if someone knows what they are doing, short of having some paperwork.