A while back i was looking for a full gasket kit. The best price i found was at PartsNMore.com for $63, but were out of stock. They just emailed me and told me they have 'em again.
I did NOT end buy from them, so I have no idea how they are to deal with.
GASKET SET - SUZUKI GS500E (89-96) 18-0163
https://www.partsnmore.com/motorcycle-gasket_sets.php?make=suzuki&category=gasket_set
enjoy!