Anyone know of a supplier that isn’t Adams Elevator that supplies the door lock contact blocks for the 3300?

There's a Turkish company called Alyans. Although they are a competitor, their skates and locks are identical to their Fermator counterparts and are interchangeable. https://www.youtube.com/watch?v=D9u3cC3ok54
You could also try Columbia Elevator. They too sell Fermators, but not the same model as schindler.

Us door equipment in Oxford ct has parts , 475-675-5847

If they don’t have in stock , then we also get pretty fast shipping from Germany :

Josep Monroig
Commercial Department
jmonroig@fermator.com
Fermator Deutschland - 85399 HALLBERGMOOS Zeppelinstr. 3 - Tel: +49 811 99959074 - Fax: +49 811 999590810 - www.fermator.com