Hi Henry,
I am not real sure if this will be any help to you, but here is a link to a
picture we have available on the club's web site but not posted anywhere.
It isn't a big picture and the quality isn't very good, but maybe it can
answer your question about the passenger side seat upholstery. It looks
like the pleats go completely over the top, similar to the driver side seat
and unlike the conventional seats.
http://www.imperialclub.com/YearbyYear/1961/SpottersGuide/LeBaron-Swivel.jpg
Tony added this picture years ago, so I am not sure who's car or even if the
seat covering is correct. I do know it is from a '61 LeBaron with swivel
seats.
Good luck on your search!!! I will keep my eyes open for any additional
pictures/information for you.
Best Regards,
Chris Trettin
1956 Imperial sedan