Patty, both of them above are correct. The special plate on your pinbox is what makes the superglide work. Sue's FW would have to have a similar plate in order for you to tow it with your superglide.
However, Pullrite has a new type of "capture plate," the plate that's on the pinbox. With this new "Quick Connect Capture Plate" the plate goes on and off with just four setscrews. Your capture plate has several screws and is not real simple to take off and put on hers. With yours you'd have to drill holes in her pinbox. But with the quick connect capture plate, you could just slip it over the pin and tighten down the four setscrews. The quick connect capture plate is made for specific pinboxes so you'd have to be sure to buy the right one.
The quick connect capture plate is about $95. I know because I'm currently in negotiations to purchase a superglide. And I'm going with the quick connect capture plate to make it easy to remove in case our Montana has to be towed by a non superglide.
As an aside, with your current capture plate you'd need an adapter for anyone else to tow your FW with other than a superglide. That adapter is something like $140. But for $95, you could toss your current capture plate and get the quick connect.
Here's a link to the quick connect. There's also a link there to a pdf showing which models fit which pinboxes.