It was an option in 1988, for sure. It is standard on a 2004 Classic 25. I don't know about your year, though. I expect the current one will fit your trailer, but the cost from Airstream might shock you. I found one at an RV wreckers yard for a few dollars, but decided it would not enhance the interior. I keep my chairs in the rear streetside locker, near the water heater. Nick.
Nick Crowhurst, Excella 25 1988, Dodge Ram 2500 Cummins Diesel. England in summer, USA in winter.
"The price of freedom is eternal maintenance."