As mentioned the term 'Force Matched' mainly applies to Soviet/Russianfirearms as when they were rebuilt they tended not to care so much about getting the original parts back together as long as they worked. Literally would stamp out the previous number and stamp the new one in.
I have mentioned before some of the terms used collecting are a bit... confusing or misleading. This is simply due to a lack of standardization of terms. For example a force matched rifle could be considered all matching as it is matching from service, but it isn't factory original. Some collectors don't consider a force matched rifle all matching (in there case what they consider all matching I would consider factory original).
Collectors are actually one of the few groups actively destroying the history of milsurps in this day and age. Every time you switch out a part to make it 'all correct' (unless the part is broken) you are destroying the history of the firearm. Just because you know that it was switched doesn't mean someone down the road will. Then that incorrect example will become a correct example, which everyone else starts to base their knowledge off of. It is the destruction of history, though the individuals doing it believe it is the preservation of history, which is the scariest part of the whole situation (think the 'committee of public safety' during the FrenchRevolution, and how they actively contributed to the destruction of public safety).