The grind/fill with epoxy isn't the best solution. Eventually the epoxy is going to separate and leave the gun. They are frequently accompanied by bed liner over the top, which has the same problems as epoxy adhering to polymer long-term, the bonds are poor against shock and impact. It looks sloppy because it is.
Look for someone who does a good heat reduction. Cold Bore Solutions is one that is in TX. The priority should be getting a quality service, not who's closest.
I've seen "bondo" jobs by several companies go TU, haven't seen any issues with the good heat reductions yet.