I think it might be, there’s no way Anakin would be able to buy proprietary hardware or software. So either he stole it, which his mother probably would not have allowed. Or he was able to scrap all the parts together because there is a template for humanoid protocol droids that we have also seen round Star Wars. And then the software itself either Anakin programed entirely himself, (which I know he’s very smart, but even that seems a stretch) or he forked it. So it would make more sense that there was an open source catalog of protocol droid software. It also would make more sense due to the fact that a lot of people have droids, but they are not all created equal. I would think many of the droids on Coruscant were proprietary, while many of the droids in the outer rim are open source.
Probably, for there to be scraps you can easily turn into C-3PO, the official droids are also built up from standardised, open-source parts. Like, I’ve reused screws or bolts in an unintended context before, but how much could you build from a dead IPhone?
If the Empire kept more careful control over their education and production, they would probably have an easier time. It’s just that a North Korea-type space opera, where the rebels have no ships, and can only get radios that continuously play Empire propaganda with no off switch, wouldn’t make for good action sequences.