Yes, the prop was to run a generator to operate the electrical systems, as the rocket engine did not have an alternator like in piston or jet engines.
Hasegawa made a nice J8M1 Shusui that is much better, if you can find one. The Academy Me-163 is a nice kit, and the Me-163S two seat option is a nice bonus.
German ink spot camouflage in 1/72 is notoriously difficult to do. Here is a friend's Tamiya Bf-109E, spotted using a fine cotton swab and thinned paint.
https://flic.kr/p/244hrR2][/url]Bf-109E by N.T. Izumi, on Flickr
To my unaided eye, they looked perfect. But under the harsh, unforgiving, all-seeing camera lens, I can see the hard edges of the thinned paint. A workaround would be to use fine torn sponges to break up the edges more. But considering the kit was my friend's first airplane model, it came out very well!