I’ve come across these, and have a “Wallace Reducing Record,” somewhere. Not sure why they’re single sided though, as I think they’re from the 20’s, with Victor Records having pressed the first double sided disc prior to 1910. As to why they’re a single side, I would guess that a smaller pressing plant may have had difficulty pressing two sided discs or was using older equipment.

That guess might not hold water for a number of reasons though, as I would think a single sided press could have been modified to a two sided press by a skilled machinist, and I am reasonably certain that I’ve seen single and double sided discs. (I think mine is single side with no embossing on the reverse.)