You will find these un-labeled Grover open gear tuning machines on 1950's guitars from Gretsch, like the Duo Jet, Round Up and others, as well as Martin guitars from the same period.
This set includes the original bushings and mounting screws.
One tuning machine is a little brighter than the others. It could be from a different set originally, which I think is the case. One bushing is very slightly different from the others as well. They appear to be all of the same era for sure, with only the patina on the one tuner differing, and a very slight difference in the profile of one bushing.