i think you are right ..i remember seeing something about that fan-in number. If you are sure that that HBA is not zoned to that FA, delete without problems. We always delete those entries as we decommission servers.
I am attempting to audit our array to reclaim luns that are not in use.  I gathered all of the wwn's that have masking and noticed that many of them don't have an entry in the "symmask list logins" table.  That would lead me to beleive they are no longer in use, but in fact right now are in use and the server is attached.  Is the "symmask list logins" not always accurate with what is actually logged in?
symmask list logins not showing masked hbas