The overall definition, especially the denticles, makes me think I'm looking at a Proof. However, the hairlines on the reverse appear to follow the postmint pattern of being their strongest away from the intersections with devices (when you think about it, it'll be intuitive that polishing hairlines won't weaken at the edges of devices since they're a negative on the die). Therefore, I'm forced to strongly consider - from these images - that the coin has been brushed postmint.
PR61 PS. I would like to point out that I don't collect this series, have no idea what those lines are on the reverse, and basically and making and educated guess from general numismatic knowledge. I actually hope I am wrong. The devices on the reverse actually look to have a little contrast to them.
It's Proof, but it would be details cleaned. At least that is my opinion. I could be wrong, but it sure looks like haloing around the devices.
Ok what are the lines on the reverse? Is it just your photo? Or is it some oddity that shows up on old proofs?