Hi Larry. In the 25' there are/were several sofa models. The Safari 25 A is a twin sofa model. There was also a Classic 25 with the exact same floorpan. Use this link to help in the hunt:
https://www.airstream.com/service/document-archive/
The floorplan is known as the 25A center bath. They made it for 23 years. The Excella model carried the floorpan in earlier years, you can investigate with the link above. In 2009 they replaced the sofa with the dinette in the Flying Cloud.
The 25 Safari twin began in 1997 and went until 2008.
The Classic 25 was around the same years give or take