I'm certain mine's 5V/16Mhz. It was labeled as such when I purchased it, I've successfully used this to make a 4704 converter which has the same requirements, and I've also measured it at 5.12V with my multimeter. Though it might be worth mentioning that the QMK GitHub page doesn't have the big bold message about this like the geekhack page. Though it does label VCC as being 5V in the diagram. Something that people might easily overlook.
However! This did make me take a take look at my local branch and for some mysterious reason the config.h file had that data bit set to 1. So my ProMicro has been listening on PD1, not PD0 this whole time. I set the config.h file back and I was able to type this reply out on my IIgs keyboard with orange alps.