Hi Bill. Welcome to our little corner of the 'net.
315 denotes Ryobi as the manufacturer of that router. Sears is almost useless as a source for parts and accessories for all but their recent offerings.
Are there mounting holes for an edge guide on either of your routers? These would be holes thru from one side to another, parallel with the bottom plate. If not, think you are out of luck.
Sometimes I wonder whether the world is being run by smart people who are putting us on
or by imbeciles who really mean it.