Originally Posted by
JohnDThompson
It's not the hub that makes it "Uniglide;" it's the tooth profile on the cluster. The original Shimano freehubs had Uniglide cassettes, but the OP's hub is a threaded hub for a freewheel. The black oil clip suggests a 600 level hub. I can't see the freewheel teeth well enough to determine if it is a Uniglide freewheel.
You're right, it might be a freewheel but the 600EX freehubs didn't have the bulge in the barrel, so it could be a freehub. We'd need an end shot from the drive, with the wheel and skewer removed, to be sure. However, those are definitely Uniglide cogs.