You want a full set of D mint proofs? Get a 1984 D lympic commemorative $10 gold coin. It's the only proof coin that was struck at Denver.
If your 1937 Nickel looks like this, it's a Proof. It looks like a Proof from the photo. Your coins are in a Capital Plastics Proof set holder. That is a privately made holder. You could put anything in there. The 1937 Proof set is a good one.