I think that all the disk based WB operating systems were supplied on DD disks.
Me too. I can say with certainty that all Commodore Amiga workbench disks were DD.
Now, what happened after the time C= went bust, is anybody's guess. IIRC, there were several supplier companies that just said "copyrights be damned" and plowed ahead and released products they were starting to ramp up production on when C= folded. I believe 3.1 ROMS were in that lot... So it may be that some of those came with HD diskettes. I have never seen one, but I have seen LOTS of variations of workbench disks from that time period, and wouldn't be surprised if someone showed me one, someday.
