I believe on this model, the oil drain plug is on the left side case cover at the very bottom kinda hidden behind the gear shift lever. these also had a filter screen held in by a spring and the drain plug retained both in place..
there should be a screw in dipstick on the right engine case cover. also on some of the older models, there is a cartridge oil filter that is behind a small cover held in place by 3 screws. use caution when removing to not lose the retaining spring that holds pressure on the filter.