Edit: Just looked into PolySnd a bit. I can't figure out how it's using AUTO_INT_5. There's a move.w #$700,d0, trap #1 at the beginning... so how exactly does this work?
In my local copy of PolySnd 2.47.2, which is in a pristine state according to the files' date stamps, both occurrences of move.w #$700,d0; trap #1 in the sources/statique folder are commented out ? Otherwise, yeah, it shouldn't work.
Looking at it, there's a bug in GetHardware: the andi.l immediate operand should be E00000. And GetHardware should have been inlined.