I will do the best to answer your questions. I spend some time on the Savage Shooters site. The gurus on that site seem to think that the actions are pretty much the same. The finish or ports may be a little different, but the function and quality are the same. As far as the Accustock goes, IMO it is a very good factory stock. That said, if you want to change the stock to something specific I would scrap the idea of getting this gun all together (I'll explain in a second). With the barrel length, savage must think that the .204 Ruger only needs 24" to stabilize with whatever twist they are using. Also, I don't think that the extra 2" would give you a ton more in the way of velocity.
Okay, if you don't like the idea of the accustock, or really want to put an after market stock on that gun right away. I would consider looking looking into a barreled action from Northlander on the Savage Shooters site. I looked, they have 26" barrels and a few different actions to choose from for a .204. Check it out.
Northland Shooters Supply