Originally Posted by oneclick

Yes, though in your case it may be difficult. Without a spoke-protector it is easier.

English-threaded Normandy and Atom and (some?) Maillard hubs have a groove machined around the freewheel seat outer circumference. It can be seen in good light if that part of the hub is clean - look at the centre where the light reflects and it should be obvious:
You have a spoke-protector which may well obscure the ring location. If so you could fashion a feeler from a bit of stiff thin wire and check for the groove from between the flanges.

And regardlesss of threading before you consider re-using those hubs check the cones for pitting. They all pit, and most of them sooner than they should.