If you are talking about where the exhaust adapter fits into the lower unit halves....there is no gasket shown on the exploded parts view.
K&B has never had a gasket where the powerhead and lower unit mesh together.
Even if there were a gasket or o-ring seal,forget about it....and just let her spit.That slight exhaust "spit" [leak] would do nothing to change the 7.5 outboard motors performance.
Rod Geraghty