Ted, I talked with Steve (Savparts) about mine a while ago before he retired, actually I just sent him another email yesterday but haven't gotten an reply yet, anyways, all the C's used basically the same parts except the 284. He quoted me a price of $60+ for a 284 bolt and I think the action was longer because the 284 has a longer case than the other calibers it was offered in, I'll go mic mine later and see for sure.
Oddbawl, Doug Murrays book on the 99 is an eaay way to learn the model designations or wait another 4 days and I'll send you a link to an article I just wrote on model designations that will be up on Savage shooters on the first of the month.