It is a proof that someone had private key to puzzle 66 year before it was officialy solved.
No, it is not. If you have any address for some compressed public key, then you can safely convert P2PKH into P2WPKH, and it will be standard. For example:
P2PKH: 1111111111111111111114oLvT2
Script: 76a914000000000000000000000000000000000000000088ac
P2WPKH: bc1qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq9e75rs
Script: 00140000000000000000000000000000000000000000
And if you know, that instead of those zeroes in the middle, you have other hex digits, then you can just copy-paste them, and change address type, as you wish. Of course, P2PKH works for both compressed and uncompressed keys, but P2WPKH are standard only for uncompressed ones.
To make a valid transaction you need a private key. Period.
The transaction we are talking about was made from bech32 address created from the same private key that puzzle 66 address containing funds. And it was created about a year ago from now.