Yes, turn signal flasher. Smear some dish soap all over it, and you should be able to work it off. The notches holding it back are square, so it's kind of a "one way on only" scheme so it doesn't fall off. Looks like your front rim is for a large diameter drum brake hub. So it was probably intended for the rear. That's why the spokes are bent and it looks laced wrong. Save all the stock parts. Nice condition stock pipes etc. are worth a lot if you're restoring. Likewise the rims, really nice original Takasago are hard to come by. I've bought many rims from Mike's. Very nice, but sometimes need some massaging. You need to pay attention to get all the parameters right to not get a problem like your front wheel. I think most people are up to building their own wheels, but correct parts are essential. Could be crazy hard to figure out a problem if your inexperienced and the parts don't all match. Paint your frame with single stage 2k urethane. Powder coating is not better - opinions vary!