I don't think the stock matches the SN , the last 3 on stock do not match last 3 on receiver.
What else doesn't match? Another parts gun?

Photos --> https://sportsdad60.smugmug.com/660771-Savage-99R-1951/n-29bSHR

[img]https://sportsdad60.smugmug.com/660771-Savage-99R-1951/n-29bSHR/i-SsP8VM8.[/img]

In the 50's, the stocks were stamped with an inspection code rather than the serial number like they did earlier.

Thinking it's probably correct. Should see the same inspection stamp on forearm, buttplate and buttstock.

In those post war guns, the rule of having the full serial number stamped on the forearm and butt stock does not apply.

Looks to me like a straight rifle, even condition all around. As others have said the number match isn't critical.

Sometimes I wonder the value of sweating over serial numbers. Sometimes the right parts are good enough unless its a real special specimen. That 99R looks like a solid rifle to me and far from a parts gun.

If it was a vaunted Winchester model 70, no collector would care if the stock had been replaced, if it was still correct in configuration.

Okay, this one goes up for sale in the WTS forum.
Thanks fellas!

It is interesting that the Model 54 isn't nearly as valued as the Model 70 even though it was the same rifle sans extraction on bolt and floor plate release to unload.
And another mystery is, there is not nearly as many 54's as 70's. Grandfathers to fathers regarding design!

Personally, if I was drawn to Winchesters it would be to the 54 way before the 70. As you said, it's pretty much the same beast.