Remington 700 SPS...20" tactical barrel but mounted on the varmint stock?

I bought a Remington 700 SPS in 308 from a friend of a friend. It has the 20" tactical barrel but the non-adjustable trigger and the cheap plastic varmint stock. I got a Bell and Carlson A5 stock so I'm not concerned about that. All I'm trying to figure out is if the rifle came that way (custom order) or if it was modified that way after it was bought.