It is indeed a long action. Savage never made a 6.5-284 on a long action in a large production run, only short actions. That is the reason the barrel is roll stamped "Model 12 cal. 6.5-284 Norma". It is because that is the only roll stamp they have that is the correct caliber.
I have received several Model 12 BVSS's from the custom shop in .260 Rem, and they were roll stamped Model 10's. That is because that the only rifles they made in .260 Rem. were Model 10's.