I just replaced the original regulator on our '95. Don't know what for sure brand it was, but it was gray and I think it was a Fisher. In our case, it was switching tanks correctly but would never indicate that the tank was empty. Sounds like yours is failing the opposite way - it always indicates empty.
When I pulled it off, I discovered that the edges of it were splitting badly. That's probably where the leak we smelled was coming from.
I got a new regulator from PPL.
It's just a standard two-stage regulator with auto-switchover. Works great, though I had to modify the bracket a bit to install it - the shape is a bit different. Also, the indicators now face down, so I use a mechanic's inspection mirror to determine whether the tanks are empty or not.