I have both brick sheets and the N Scale Architect stuff is not the same as H&R. H&R is slightly larger and has crisper mortar lines. Also the H&R brick sheets were not styrene (PVC maybe?).
This might be an urban myth, but I've heard that the reason H&R bricks are no longer being made is because some drug addict stole the copper dies and sold them as scrap to feed their habit.