Hi - no markings at all on the freehub. The difference between the threaded and unthreaded freehubs seems to be that on the threaded version the splines go right up to the end of the freehub and the last (smallest) sprocket is open at the end of the grooves to enable it to slide down as far as the next sprocket. The smallest sprocket on the new cassette has the ends of the grooves closed which fits on the unthreaded freehub because the splines stop before the outer end. Hope this is understandable!! The old cassette sprockets weren't loose, just worn.
Cheers - Nick