RE: top flite p-51 giant scale build
not going to happen as far as the drilling goes unless you have a good supply of diamond or possibly tungsten bits. The Problem is that the bolts have gone through the hardening process and are most likely ASTM A574 spec or better with a rockwell hardness in the C39-C45 range which means carbide, tungsten or diamond cutters.
you have 2 options as far as bulk quantities go ...
buy all the bolts you think you will need and have them annealed ( softened ) then drill them all and have them re hardened or place a special order directly from the mfg. ( probably very expensive )
the annealing route is the way I would go as you can have them all fired at once and then bring them back to your shop and drill then have them all heat treated and hardened at the same time. Just Google for heat treating places and get some quotes and make some calls.