It's possible to investment cast bog standard PLA see the VegOilGuy on the YouTubes ...Good thinking - and investment casting can get very close (see high pressure section turbine blades in jet engines - main surfaces not machined) but that's not cheap.
A normal foundry won't do investment. A precision foundry will, but pricy. An art foundry will, but prob not the high precision needed.
And then your 3D printing material can't be any old plastic - must be a fully melt-out-able wax type -- no good if crud left in the mould on burn-out.
And then I'd say it still won't be precision enough for this type --- redesign the vice?
Ah well - maybe some other project?
Or there are special resins for SLA printers designed for Investment casting.
Ah well maybe this project