Very nice collection. I think I have 6 of them but only one bayonet (so far).
As to differences between various years. There were 3 producers of these, Izhevsk, Tula and Podolsk. Podolosk is the less common of the 3 and produced them for less than a year. Izhevsk produced them in 1940 and 41, then went back to turning out Mosin Nagants. Tula produced them until 1945. Early guns had narrower stocks, narrow trigger guards, 6 port muzzle brakes, 8 port gas chambers, scope rails and the stock only had a notch on one side of the trigger for the safety. Later guns had a wider stock, wider trigger guard, 4 port muzzle brake and a notch on each side of the trigger guard. Also, while most of the 1940 and 41 guns had scope rails, a low number of them did not. The scope rail was done away with in 1942. Some early guns also had a notch at the end of the receiver for locking the sniper scope in place.
Anyhow, these are some of the differences between years. There may be more and I may have some of this incorrect but that's how I understand it from my research so far. Some models were quite low in production and bring a fair dollar, particularly in the US.