How To Tell A Jefferson Proof?

I'm not sure either, since I've never seen them personally, but there are two things you would most likely check for first. If it has a reflective surface, it probably is. You probably checked for that, so that may not have been so much help, but more importantly, since proofs are struck with higher pressure and are done more carefully, you would check to see if it is fully struck. It is very rare to find full step jeffersons in that era to my knowledge, so if they are indeed, that makes it very likely to be a proof in itself. For anyone that may be wondering, the full steps is referring to the 5 or 6 lines, or steps, that appear that the bottom of the Monticello on the back. They are completely smooth on the huge majority (from my experience) of older jeffersons, mainly pre 70 in my observation.

I would think the edge would be the key. The edge should be full all the way around the coin and it should meet the top surfaces of the rims at a nice squared off corner. Even the poor quality brilliant proofs of the late fifties and early sixties should still have those full edges.

Need those pics

I agree with upstate. Mirror fields.