The one that originally came with Mark XVI. At that time I was offered the first generation like yours. I choose the newer one. Now slightly regret the choice. This week daily watch : Seamaster Commander's watch. ...
Before the cancer that is George Kern started metastasising across all their product lines. I have a 3705 and a 3251 (alas on strap, not that wonderful bracelet) from this era. I shall post them in the IWC forum.