> had heard of these two on 12" before but I didn't know that they were pressing
> 12" singles very extensively in the '60s-early '70s.
That's because they weren't. The first commercially issued 12" was "Ten
Percent" by Double Exposure in 1976 on Salsoul Records. . There may have
been promo 12"s for disco dj's in '74 or '75, but I've never seen one
ealier than 1976.
Anthony