Warcradle Games have been releasing some of the models through Wayland games in limited print runs. Basically casting to test moulds and selling the produced models.
They are only (currently) casting anything that is resin and have not touched the metal parts and thus also haven't sold any models that require metal components to function.
I also don't think they are doing any parts to order nor any replacement parts service. At this stage its purely mould testing. You might contact them and ask about the potential, but chances are they are mostly going to focus on their own lines coming out "soon" (the rules open beta is running right now).
https://www.dakkadakka.com/dakkaforum/posts/list/708649.page
https://www.warcradle.com
https://community.warcradle.com
Otherwise hounding Facebook groups might get you what you're after in spare parts from other gamers.
https://www.facebook.com/groups/sturginiumlounge/