Can't prove anything (yet maybe) because of a serious TWO hard drive crashes, but those look an awful like the ones I did as FW2 @ MasGrafx years back. Since the 1, 5, 6, 7, 9, and 0 were made up to finish a complete set, I find it hard to believe years later someone would happen to create those missing numbers exactly like I did years ago.
If you redid them in a resolution better suited for 2048, that's fine. If you just wanted to make them available again, that's okay too. I made the set I did for people to use. But if this is the case, give credit where it's due. I can get a copy of my original set, or I may have saved them on a cd.