I highly doubt there were any military grade custom amiga chips ever made. Perhaps some of the "glue logic" ICs on the original A1000 might have been such parts, but considering the cost difference...?
My understanding of military grade is the chips have simply undergone more rigourous testing before packaging, nothing more. Basically, they're certified by the manufacture to withstand a bit more abuse than consumer parts.
Standard military grade ICs can be identified by a "54" number instead of "74". In other words, it's written on the label rather than a type of packaging or pins or whatever.
