Is This A Regular Proof Set Or Mint Set? I'm Confused (1964)

That is a proof set.

The color/reflection should tell you it is a proof set:

It should be this evident. Proof coins are struck as proof cents. (actually struck twice) Business strike cents are only struck once. Business strikes can't be proof coin. But proof coin can be impaired (damaged) and still be a proof coin.

Two things tell you instantly that this is a proof set without even looking at the coins. The plastic on the mint set is trimmed on the edge with either a red or blue strip, red for the Denver coins, blue for the Philadelphia. The "token" in the proof set is a thin multi-sided metallic thing. In the mint set they are round gray plastic disks. With those two clues it is clear you have a proof set.