Sometimes there are really obvious revisions to parts. For example early E90 N52s got metal thermostat housings. The replacements are all plastic now. So if you pull off the thermostat housing and it’s plastic it’s been replaced at some point. There are more subtle things like that. The N52 again factory aluminum bolts have blue paint but none of the aftermarket replacements are marked blue.

Most people don’t keep track of this stuff and don’t really know as others have said.

It’s the usual for Reddit. If you insult sacred cows the pitchforks come out and something you probably already spent way too much time working on now requires even more time investment to defend. Refusing to respond just means their version of events wins by default.