Removable Pin Box?

I know a couple of people with Sidewinders and they work good for what they were designed and allow the tongue to swing completely out of the way when unhooked. The bolts on your pinbox are capable of being torque to spec more than once just like your wheel nuts and most are grade 5 bolts making them less brittle. If you are really worried about the pinbox bolts holding your upper 5th on change them out for grade 8 fine thread with stover nuts and they will exceed the strength of the mild steel at least 10 fold. Lock washers are old technology leaving scars on the parent metal and nut faces. Nylock and stover nuts are much nicer leaving no burrs behind to catch things on. Torque wrenches were designed to set and reset bolts as needed unless there is apparent stress stretching or damage to the threads they should not need to be replaced. Overzealous monkeys in shops with high output impacts will stretch bolts on anything before most people will with a 1/2" ratchet.