Hello I accidently damaged the threads for where the bolt goes in on the right side. All the other bolts are tight and one spins. Do you think this will be a problem?
I personally would likely seal the area around the stripped bolt with a small amount of gas safe RTV on both sides of the gasket. Put it together and cross my fingers. This goes double if the bolt is giving even a small amount of clamping force.
Using a helicoil seems over kill for such a small bolt. Remember the torque is only supposed to be 10 Nm (89 lb-in).
An old timers option is wrap thin copper wire around the bolt to "take up" some of the space lost by the stripped threads. Likely for the size bolts used on the gas tank will need fairly thin copper wire. Perhaps remove the insulation from lamp cord and use the individual copper strands.
You should be fine, it's not under any pressure really so the other 5 should really hold it in pretty nicely. The manufacturers tend to put in a few extra bolts on any gasket surface just for something like this. The clamping pressure of any gasket is based on the bolt size, distance between bolts, and the gasket surface area. Sure you can use sealant but you might not actually even need it.