Cartier Tank Louis ‘Jumbo’ Automatic - case back stamp question

[kmacfarlane]

Hi Forum Members - After a number of hours researching an Automatic ‘Jumbo’ Tank Louis I picked up 3 years ago, I still have a couple of questions that I’m hoping fellow forum readers can help me answer. I’ve determined I have the slightly smaller Small ‘Jumbo’ sized dial variant from 1977 or later (Cartier secret signature on the Roman numeral 7 didn’t appear until 1977). However, I have not seen a similar small ‘Jumbo’ with the same dial - Swiss plus the Cartier Secret code. I’m curious if the group thinks this is a replacement dial or just unique to the small ‘Jumbo’ from 1977 or later. I’ve actually asked George Cramer (Cartier guru the same question but he didn’t know). Also, the rear case back has two things I haven’t seen on another Jumbo Automatic tank. First, an 18k Swiss stamp. Second, a small stamp below the Paris (lower right corner of the picture). My initial thinking on the 18k Swiss just wore off on most models. However, i have no guess on what the small stamp under the Paris on the case back means. Any vintage Cartier fans out there who can help me?