I didn't even know Murray (Siemens) had any 3 phase equipment unless you have a really old (pre- Crouse Hinds) panel. Siemens marketed the Murray line as residential. I also don't think I have ever seen bolt in Murray breakers.
It's kind of a moot point anyway. Murray circuit breakers were discontinued by Siemens last year. The rest of the Murray line will be discontinued this year. Siemens has a cross reference chart you can show inspectors if questioned that Siemens breakers are the replacement for Murray.