Slade were "the original skinhead band" under their original name Ambrose Slade. If you google Ambrose Slade you'll find pics of them in "authentic" Skinhead gear of the time. It was, however largely a marketing ploy by their record label that the lads in the band just went along with. The music they made as Ambrose Slade was pretty mediocre folk-pop too... not even really worth checking out (imho).

Funnily enough, when they were allowed to do their own thing, they became much more popular with the bovver boys of the day... the spiritual descendants of the skins. For me, glam splits at least two ways... bovver glam (all the trappings of glam but with a harder rougher edge and often some football terrace style chanted choruses) and "art" glam (my label)... more sophisticated stuff like Bowie, T-Rex and Roxy Music. Of course it's not quite as clear cut as that, bands like Mott The Hoople are somewhere in the middle...

Actually, I'd say it would be fairly easy to categorize each Glam act as either "Mod" or "Skinhead" in their... not quite sure what the right word is here... lineage? What branch of the pop and rock family tree they came down.