how portable is a FreeBSD SPARC64 sysdisk?

[Steve Rikli]

I'm thinking of migrating webserver duty from an Ultra2 running
FreeBSD-6.2 to an Ultra60.

If I take care to mind the SBus vs. PCI and corresponding device
names/numbers for e.g. add-on NICs and SCSI controllers, is this
expected to "just work"?

I.e. is there anything Ultra2-specific vs. Ultra60-specific in
the GENERIC kernel?  Other gotchas from anyone else who's done
this sort of thing?

Cheers,
sr.