I think they should have fit the cal. 5134 to a thinner case, the ultrathin movement is 4.31 mm while the case is 10.9, ok the new thicker glass but 6.6 mm over are too much, in my opinion.
I have found several ref. 96 (also a ref. 453) in the range 827.132-828.158 manufactured between the years 1935-1937; the number produced during these early years can be around 550 pieces, so the total number of 12SC is increased up to 1.800. I have also noticed that those calibers in the range 861.
... I give my answers, fingers crossed 1 hands, special degrading tapisserie, minute track; 2 Ferrari F1; 3 Alonso; 4 titanium/ceramic; platinum/ceramic; RG/ceramic; 5 two pieces dial, special tachyimetric bezel. Do I win something? ;-) Happy new year to everyone!!! Lorenzo