Are the RT2 and DT360A the same gas tank just painted different colors? 

No, different items.

If you're looking for a correct one to paint, then the same tank (different colour) is fitted to the 1974 DT250A.

The 1974 DT250A and DT360A tank was a one year model only item.

Well, I just fitted a DT250a tank on my RT2… fit is fine… the only reason is for the flip lock cap and holds a wee bit more fuel…
Yes the tie down at the seat is a bit different… So my MX tank is on the 250…. Just a rolling heap while I get the RT sorted..
Sneezles61

Thanks Sneezles and that's good to know.

If I was going to the expense of repainting a tank, then I'd rather it was an original fitment.

I really don’t believe mine is original… someone before me swapped a few cosmetics out… for now, it’s all getting primer and clear coat… Making it a bit fancier just isn’t in my present day thought.. (:
Sneezles61

Fair enough.

I'm in the keeping the patina camp and only repairing/replacing what is necessary. However, I made my previous comment in the light of Eddy's other post, where he was asking if anyone knew of a painter for his tank.