pg_dump and sequences (bug ?)

Using pg_dump from postgresql 7.3.4 I've obtained
a dump file containing a SEQUENCE SET with no
corresponding SEQUENCE. I've seen that this is usually
due to the presence of a table with a 'serial' field,
but since in this case there is no such table I wonder
if this is a bug in pg_dump.

The only reason I can imagine for this is pg_dump taking
any sequence whose name  ends in _seq as being associated
to a table, no matter if that table exists and has a 'serial'
field. Is this possible ? Shouldn't this kind of dependency
be coded somehow ?

TIA

--strk;