I pretty much always use no gasket, if they are not flat enough to seal up you got an issue you need to fix. The factory never used them. One less gasket or sealant to blow out into the pan. If it leaks it would be very tiny and not worth any fuss. One time I had one where it looked like they had an extra dull cutter machine it and I used a very thin coat of right stuff, I think it would have probably been fine with out.