This is why what's left today is so expensive. Because they were plentiful and people hacked them. There are also different styles of collecting. Everyone wants a mint #s matching Garand or Springfield. When it comes to Mosins that criteria is of course a huge plus but people collect them for their uniqueness and battle use. For example one of my Mosins was made in 1901, captured by the Austrians in WW1, had things changed by them. Then sold to Finland and used to fight the Soviets in the winter war. Later is was most likely re captured by the Soviets because it was sold to the Balkans. Contains markings from all Imperial Russia, Austria, Finland, and Serbia. Also looks like the Austrians re chambered it for 8x50R. It's full of European history from the first 50 years of the 20th century.
Then there are ones that you really have to know what it is your looking at. You can have a early 30s typical 91/30 and think it's just whatever when in fact it came from the Spanish Civil war. They have a few tell tale signs but they are easily overlooked by someone who thinks it's just another 91/30.
Btw, one m38 carbine just sold for $1500. No import marks, none referbed, contained the early sale sight base of the M38 and Fin capture. The last part is really what makes it rare as there were not a lot of M38s used against Finland. An M 44 would cost even more and be even more rare cause there is something like 120 known Fin capture M44s