Depends on a couple of things. Which way you wanna go (L or R) and if you have enough fence rail to support it and if the fence can reach it if you intend to use the TS fence for route purposes. The biggest issue is structural support for the cast iron table being added on as an extension. It's very heavy and most likely should have legs holding it up. Going right will be less of an issue, going left can be much harder depending on your set up. Its a Unisaw so you most likely have more rail on left side because US's are right tilt, also may have to drill matching holes on the outside of your cast iron wing to add the router table to it.
It can be done, just need to make sure you have the proper structural support to eliminate any sag and keeping the table surface in equal coplanar across the length and back to forth. It's going to want sag.