Hi Doug
It's been awhile since I logged in here, but I just came across your post. Setting aside the Commercial Chassis and the Series 75 limos, yes, you do have a rare sedan.
There is a site devoted to 61 and 62 Cadillacs that I'm a member of and would encourage you to join also. The amount of knowledge and enthusiasm for these cars is overwhelming and the site is growing daily. I'd encourage you to join us at
www.61-62cadillacs.com - if you do, don't forget to list your car in the registry. We're trying to document as many of these cars as possible.