If you can determine the rod diameter and spacing that will fit your router you can then look at other brands or models to find an edge guide that will fit. The DW6913 edge guide that DeWalt sells for their newest routers comes with 2 different sizes of rods and the guide has 2 different spacings that it can handle, so it might just fit your router, but the clerks who take the orders won't know this as their computer data won't list it. You will need to measure it yourself. Since BD and Dewalt are and have been the same company for many years it's quite likely that it'll fit. I have the DW6913DeWalt edge guide for my DW618 router and found that it also fits a 40 year old B&D router that I have by using the second (smaller) set of rods that came with the DW6913. I'm willing to compare your measurements to see if it will fit your router if you want.
Porter Cable makes an edge guide that attaches to a plate that has several sets of threaded holes for attaching to several different rod sizes and spacings, and it might fit or be easily adaptable to your router (maybe by making a new plate). It is a long extruded aluminum bar design with micrometer adjustment and is very easy to use (actually better than the DW6913). If not, check what is available from other brands. You will probably need to go to a shop that carries several brands and take your own measurements on what they have in stock as none of the manufacturers list the sizes and spacing of the rods for their edge guides. It's amazing how many times that I've found parts that are inter-changeable between brands. I recently discovered that Porter Cable router collets for their latest routers are identical to those used in my Delta router/shaper and I discovered this 2 years before BD/DeWalt bought Delta and Porter Cable.