Over cleaning can, and a strip back certainly does. A full back to metal, and back to white wood, takes all the history off. What is funny is that some of these full stripped and refinished end up superior finished to what would have come out of the factory. I'm not a fan, but they are good to use for another "many years".

What is often important is to stabilise and stop further damage. Its quite a challenge to know how far to go, and very easy to go too far.
On the whole a honest gun will show its age somehow. A well used gun can't be made factory fresh. Given enough time no gun can stay factory fresh; though the paraffin/paper method can get close.
Most collectors want "honest".

The thread example looks fine. Not too much, but just enough to show how clean an example it is. Importantly enough done so it should stay good for a good time.
Long term storage is difficult because it doesn't take much for some tiny rot to take hold. One reason I gave up collecting.
The 1980's onward collectables can be had BNIB, but even those should be checked and wiped every few years. Rejuvenate the oil. Every time something might have attacked them. Leather, PFE, plastics, and some paint will deteriorate just by time. Heck, even the box and packaging can self destruct and do harm in some cases.

Its hard to keep guns "perfect".