i noticed the chainguard youve got on the bike has been chopped and messed about with - if you want to restore the bike to original, id suggest you keep an eye out for one starting now, because theyre notoriously rare
same applies for the correct mudguards - if you havent got them, its never too soon to find some
the engine is stamped 99c? thats odd, to my knowledge the model 99 was usually stamped with '14' to denote the model
anyway, looks like a great project since you seem to have all the bits. be sure to keep track of all those nuts bolts and studs, its painful trying to track them down when you havent got em; theyre available, but disappointing to have to stop for the sake of a nut