I think the idea of seasoning presumes that the rifling is a trifle rough from the rifling cutter, when first received. I don't think that is true for the vast majority of guns. I also think that for a rough barrel to be polished after only 150 shots is questionable in the sense that it would presume a moderate amount of wear over a relatively few shots. Some people have told me that they felt their barrel had become worn out after 10,000 shots or so but that is an awful lot more shooting that 150 shots of alleged polishing. The gun involved also had relatively shallow rifling to begin with (.005" deep) and was by no means a smoothbore when finished. Possibly using patches with grit in them could accelerate wear.
cheers mooncoon