In reference to the post above differentiating between an early 43 fighter and a "late" 43 fighter, I would not go as far as to say that steel wrist thong link fighter is late 43. The brass thong link was relatively short lived due to several reasons. One, brass was a regulated commodity by the WPO, and therefore not too easy to acquire through normal channels, particulary when you were low in the pecking order as was RMK. It is well known Bo often search junkyards looking for scrap brass or bronze for hilts and such. Secondly, the brass links were soft and tended to collapse with little force.
The steel link replaced the brass link in my estimation during the first half of the year. That is not to say a brass link was not used after a steel link was used, but for all practical purposes, the brass link preceded the steel link.
The following photo is of a reverse quillion 1943 fighter. You will notice the orientation of the brass thong link is pointing opposite of what was standard, towards the edge of the blade. This orientation would facilitate its use on an "edge-up" fighting style, a method of knife fighting Bo was promoting to some degree at the time. I believe this is the only knife/thong link I have seen set up in this fashion.