Awesome help Oscar. This has the short master cylinder plate from the side rail and it attaches pretty far up on the U section. It dose not appear to have ever been yellow. It looked like a pretty stiff chassis to me. The brakes are indeed a pretty modern design, unfortunately they are in terrible condition. This thing has never had a new bearing in its life either!
On the plus side it has a new front bumper(installed upside down), new body work(mounted to rub 2 out of 4 tires), a new seat(pinched in between uprights) and a new radiator!