Thanks Cliff.
I have one or two, but I was too lazy to go find them.
The 79front/78 backs were originally sold by a dealer I think from the Baltimore area, in strips. What I heard was that they knew where Topps printer dumped trash, and had a bit of a find one day being there at the same time as the truck that had Topps stuff.
I have a strip I ordered back then, not sure where it is but I know I didn't cut it. It got a bit squashed in shipping, put me off mailorder for a few years.
Topps must have had a ton of leftover 78back only sheets.
Steve B