It will be very strange and funny if there is a registry of 3D printers before there's a registry of guns, and for that matter, it will be very funny if it becomes easier to buy a gun than a 3D printer, with the reasoning being that 3D printers can print guns.
I highly doubt we would send goon squads door to door to check your firmware. Then again, given today's situation in MN, I wouldn't rule it out either.
The text of the bill suggests that it would make printers capable of being reflashed with an open source firmware illegal to sell, as the legal requirements for the blocking would include preventing it from being circumvented. The law would also make having a printer sold mail-order into the state illegal entirely. It’s not clear how parts-built machines like Vorons would be handled.
It appears to only cover sales, however. Possession of files for firearm components would be made illegal, but seemingly not a printer without the restrictions.