Thanks Zap, yeah I was thinking a top and bottom mold cast in aluminum bronze could work but at that point I'd just mill it. Either way, it'd be more prototyping time and my OCD has been satisfied on holotags. I've got a new laser cutter and CNC router kit to setup before I think about the cast bottles.
If I was doing a run, I'd skip the stamping. The pewter weight just feels good. I'd do larger scale pewter spin casting (to reduce the finishing time), custom flexible pcb, ninjaflex silencers, and the acrylic lens inserts. Wiring the trinket was very fiddley.