They are smaller than the GW big hat chaos dwarfs.
I think they look OK. I know it's hard to judge fully from small photos, but there isn't anything that immediately betrays them as recasts.
The seller is correct, however, the CD-A and CD-B mail order Chaos Dwarfs that are shown really are smaller than the plastic Chaos Dwarf Warriors or the big hat metal ones... but I don't think in-and-of-itself that the comment is any indication that they're recasts.
Yeah I just read about a guy on BT that got hosed on ebay for similar stuff, i felt bad for him. I’ll keep an eye on them though. Just in case I ever need another 15-20 figures for an 8th edition horde!