I can't find any 45/70's in stock. But I will keep looking.
If I do they go from about $20 more than the 300 ACC one to $110 more for the Buffalo Classic.
From the H&R site it does not look like they make a 45/70 with threaded barrel. BUT.. The handi rifle in Marlin 444 has a threaded barrel. Same price as the 300 ACC.
If you want I will look around and see if other vendors have the 45/70.