What`s the big deal with all numbers match rifle?

I Attended a gun show in my area today and found a selection of Mosin Nagants and prices varied 225-325$. I happened to have a person looking over my shoulder while i was looking at several surplus rifles. So this person gets a nod from the seller and receives the expert on mosin nagants recommendation. He looks at... show more I Attended a gun show in my area today and found a selection of Mosin Nagants and prices varied 225-325$. I happened to have a person looking over my shoulder while i was looking at several surplus rifles. So this person gets a nod from the seller and receives the expert on mosin nagants recommendation. He looks at all the numbered pieces and nods okay. In reality i liked one with a nice stock with good bluing and bolt worked nicely and didnt fall open with handle up when i pointed the barrel up.The numbers did not match but was cheaper enough to sway me.
Update: I bought it. When i got home i measured the bore with a inside hole mic from craftsman which are the kind like a ball split on the end and you turn the end to make the ball bigger then measure with calipers. I measured .303 with a little over. I did turn it opposite of rifling twist as i tightened to slip fit. I... show more I bought it. When i got home i measured the bore with a inside hole mic from craftsman which are the kind like a ball split on the end and you turn the end to make the ball bigger then measure with calipers. I measured .303 with a little over. I did turn it opposite of rifling twist as i tightened to slip fit.
I bought a box of 7.62-54r also. I took a new round and grease-stuck a shim cut out of the thin
Update 2: part of an aluminum drink can and stuck it on the face of the cartridge and loaded it. The bolt handle closed but it felt a little more resistance than without it. I remembered that bit of advice on yahoo answers-hunting section about 3 years ago. I believe i have a safe shooting rifle but not necessarily a... show more part of an aluminum drink can and stuck it on the face of the cartridge and loaded it. The bolt handle closed but it felt a little more resistance than without it. I remembered that bit of advice on yahoo answers-hunting section about 3 years ago.
I believe i have a safe shooting rifle but not necessarily a collector even though some parts are not original.
Update 3: So which is the most important, a rifle with all matching number that may not be safe or one bought like i just described? Even if i bought a collectable i still demand it to be one that i can shoot. Am i too picky?
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