I quite often use a shorter bolt and/or a thin washer compared to what's called out. As long as there is thread out the end of the nut it is okay.
The only issue I see with replacing all of them is having to pay for that many more screws. If it were me, I'd just replace the wrecked ones with the shorter screws.
Not always.
Most fasteners in a RV are loaded in shear. For a structural fastener to properly carry the shear load, the parts should only be baring on the un-threaded shank of the bolt. In many instances, if a shorter bolt is used with a thin washer, there will be sufficient threads (minimum of one) showing outside the nut, but a thin part of the stack up may be baring on the bolt threads. Not a good practice.
