Hello all, I'm crossposting this question from the Vintage Centerfire forum, but hopefully I can get some clarity.
I inherited a Model 99 in .300 Savage a couple years ago, according to the serial list on this site it was made in 1953 (it's got the round counter and the ready-to-fire pin indicator). In order to appease my roommate I had removed the bolt assembly and kept it separate, but now I can't find it, so I have a useless gun. I hope to remedy this so I can use it for what it is meant for, shooting! I have a couple questions about sourcing a replacement:

-How do I tell if the model is special at all? I keep seeing listings and posts about things like 99C, 99F and so on. Or do I just have a plain old 99?

-The firing pin is normally part of the bolt assembly, correct? It's been 2 years since I took it apart, but I removed the whole bolt assembly I think (for ease of re-installation).

-For the bolt itself, I found this (https://www.gunpartscorp.com/products/1000630) and heard it was a generally reputable seller. But is that a typo for the S/N? It says 90,000 or under, but that would appear to apply to almost no guns. For reference, mine is 715245. And this would not include the firing pin assembly, would it?

-I'm attaching pictures so you can get an idea of what I'm missing, but I think I need:
-Breech block
-Firing pin
-The breech bolt stop and screw

Here's the pictures, with the stock removed:






Any help will be greatly appreciated. This is my first gun, it belonged to my grandfather, and I just want to fix my blunder and get to actually use it. Thanks!