Bought a used MacBook, has someone been inside it?

Hello all,

As the name suggests I'm a bit of a worrier. However I have always been proudly pro-second hand. I've bought all of my ipads, macs and iphones on eBay for the past decade or so with no issues. However, recently something in my brain has switched.

I bought an 'opened- never used' M3 Max Macbook Pro for a great deal and excitedly waited for it's arrival. When it did, it was indeed in perfect condition, boxed with all sheets and pre-packaging included, the charger hadn't been touched. Great!

I turned it on.... nothing. No power- weird I thought, I'll charge it up - and sure enough that worked. The mac went straight to recovery, it had been wiped but MacOS hadn't been re-installed. I wiped it again using Disk Utility and hit re-install.

Uh-oh, it was Activation locked!! Alarm bells are ringing at this point, but I decide to give the seller the benefit of the doubt and contact them. Sure enough they apologised and logged out remotely. It was at this point I started to get majorly paranoid, why was it drained to 0% battery? Why had they wiped it but failed to de-activate it in the process? In fairness, the seller had been extremely polite and helpful, so I couldn't justify sending it back at their expense.

Also for all intents and purposes the macbook was working fine now. It isn't enrolled in any management, activation lock is now disabled. All seems well. I also used my MBA to perform a complete DFU restore on the machine.

But still, I opened it up to have a look inside, to make sure there's no 'false chips' or some kind of keylogging hardware. Like I say, my paranoia kicked in. I had no idea what I was looking for. The only thing I thought seemed out of place was this one pull tab (for the keyboard, circled) looked extremely creased. Could this be evidence that the previous owner had tampered with it? Or is this generally how it looks from the factory?

Anyway thanks for reading- despite the deal this was still a huge purchase for me, I think the stakes were just too high!

TL;DR: I noticed this pull tab had been disturbed inside my Macbook, can this be from the factory assembly or is it definitive proof someone has tampered with it? Note: I disturbed the trackpad cable myself while opening it, so it is slightly askew- nothing else has been touched (by me).