I always hold the new filter gasket up to the old one just to make sure they have the same gasket size, just in case the robots at the factory were trippin' on peyote.
If the threads spin good and cinch up to the case, that part is OK.

I blew 80 psi oil all over a Case loader for that reason, now I check.

2005 Model . Two Fast Eddy stickers , a bell and a clock . She's Lola . She tinkles and keeps time . http://s649.photobucket.com/albums/uu211/britbike05/