Why do you doubt this?-----There is no cylinder head that you can remove !!-----Pistons go into a blind hole from the other end.-----The block and the dome with the plugs are ALUMINUM.----Cast iron sleeves are inserted in the cylinders.
These newer inlines use " cracked rods " and no need for fancy ring compressors.---Remove and install pistons one at a time.-----Flywheel and hub are easy to remove.----Careful / take time to get rod caps installed correctly.----They only go one way.
There is no " head gasket " on your motor.----Perhaps the water jacket might be leaking.-----Not clear in the video.-----Water appears to be streaming from poppit valve vent.
Leave it in forward when you take the lower unit off.----Replace impeller.---Slide it back together.----Have an assistant rotate flywheel to engage driveshaft splines.----Easy project.