I never inspected the cavity where the oil filter is located,but I see there is no access to the sump except the half inch hole the filter bolt screws into. Are you remembering a different bike?
I agree with Jimmymac, but would add, unless the seal has metal reinforcemnet in it? (like some fork seals I've changed)... but if it's JUST rubber...yeah who cares?
WOW T Cro! that is ugly! (if you don't mind)... what's the story behind that? Or point me to a previous post about it?
but like I said "any metal" I would be getting that seal out of there! and if it was my bike... even if there wasn't HAHA