Trimmings are just that, trimmings. If you were to go to a decent butcher shop or meat dept at a grocery store that does their own cutting and wrapping, they'll have trimmings for you. At least around here they do. Just advise them you want pork trim for making sausage. Last trimmngs I bought were 1.10$ and they were just that, basic fat trimmings. Last yr I got a hold of lean trimmings and used just that, too lean was the result. But if you want lean trimmings, watch the sales ad for when the butcher shop/grocery store has center cut pork loins on sale, then you can get lean trimmings.
So yes, I would think the pork loin trimmings would be what your looking for.