Or at least, it appears that that's the case, due to personal testing and there being no mention of RefreshParts() in https://github.com/vgstation-coders/vgstation13/blob/Bleeding-Edge/code/modules/hydroponics/seed_machines.dm
I'd expect upgrades to make the machines work a bit quicker at least, even if you're unlikely to ever get better parts.
You're likely to get upgraded parts if you bother to ask R&D, I suppose. Or just play as a research Botanist and make the parts yourself and drag them to the outpost.
Resolved by #18138