The Series II K17S has a pressurized oil system and an optional oil filter. It is a completely different matter than the Series I, which did not have a pressurized oil delivery system. The Series II is a much more reliable engine. In fact, as problems with the Series I began to crop up, Kohler itself told mechanics to avoid rebuilding the Series I as they came in and to replace them with the Series II instead.
Use it as yer replacement and get the optional filter if you can.