A recent comment was made at Autoblog that made me wonder. Dinger said,
The 900 of the 80's, the "C900" (c denotes "classic" to seperate it from the Opel based 900 made form 94-98) was made from 1979 to 1993 ('94 for the convertible). The C900 was based on the 99 which was introduced in 1969. In fact the door from a 1969 Saab 99 will bolt on to a 1993 Saab 900 and fit perfectly.The surprising part is the last sentence. Is it really possible to bolt a 1969 99 door onto a Classic 900? That seems a bit beyond belief.