Got these Roadmaster. Mixed of parts on it.
Serial number G 58772 AU
On the rear hub is a 36-13, the arm is Perry B100, England, should be a replacement.
It's good to go just as it is. I think the shockmaster springer is supposed to have rods extending from the bottom of the springs down to the front axle. But, it probably works great just like that. The front rim looks like an S-7.