With LPRng there is no reason for /var/spool/lpd to owned by lp.lp actually there is no reason for /var/spool/lpd at al except maybe for grouping together print spool dirs.
/var/spool/lpd/<printername> is needed for the current printfilteres to work correctly. That being said, I believe that even with the current lpr, there shouldn't be permission restrictions on /var/spool/lpd, only on /var/spool/lpd/<printername>.
Fixed in filesystem-2.0.3-2.