If you look at a plastic unit there are two halves and a baseplug.These are all heat welded to very close tolerances to give correct tension and wheel spin. So no, drilling one would make a mess of things.

The rare brass units are certainly beautifull pieces of machining.
There is a susceptability of the brass on brass threading to
freeze up with time. the aluminum units have that neat hex key.
Replacing flints is going to be an exercise in care with a clean surface to catch small parts.

I thought the plastic units a little more 'grippy' vs the smooth aluminum. So I did the hand in icewater and make a SPARKLITE fire test and found no real difference.