Stripped Thermo Cover bolt..help 130hp

OK...doing the right thing and replacing my thermostats on a 1994 130hp. When putting back together one of the bolts stripped.

What is the best way to get the cover bolt (#4 bolt) back in tight?

Helicoil?

open to any sugestions.

If I use a threadrepair kit.....will it screw me up next time I go to do the thermos?