No this is the whole point!:roll:
The freehub body isn't longer.
Because 6 speed has the cogs further apart, a 6s cassette fits in exactly the same space as a seven. There has never been a different freehub body length for 6s or 7s. The only difference is that uniglisde ones fitted the cassette with a screw-on smallest cog, whereas the later hyperglide (7s and up) ones had a lockring. By the time HG came out, UG was obsolete so there were no HG 6s cassettes made. So you have a 7s freehub with a custom made 6s hyperglide cassette.
The freehub body isn't longer.
Because 6 speed has the cogs further apart, a 6s cassette fits in exactly the same space as a seven. There has never been a different freehub body length for 6s or 7s. The only difference is that uniglisde ones fitted the cassette with a screw-on smallest cog, whereas the later hyperglide (7s and up) ones had a lockring. By the time HG came out, UG was obsolete so there were no HG 6s cassettes made. So you have a 7s freehub with a custom made 6s hyperglide cassette.