These bikes are so rare its hard to put a value on them.
From my experience, rare does not always equate to high value. This bike probably holds some decent value but again i would like to suggest forgetting the value and just enjoying it.
Parts aside from the engine will be impossible to find and a full restoration on one in this condition will cost way more than what they would be worth.
Unless your a perfectionist i would suggest you find a motor, clean up what you have, and just ride it! I wouldnt recommend you "restore it" if your main goal is to sell it for profit. If your end goal is to just sell it i think now is the prime time to do that.