I just acquired a Speedmaster ref 105.003-65 with a 1035 2-69 bracelet and 2 strange looking end links. They fit well, and on the upper side could pass for a #6 or #506 link. On the underside there is no marking and the design differs from both the #6 and #506. In the pictures , the strange link is in the center flanked by a #6 and a #506.
This unknown link actually fits the underside the best of the three.

Anyone have an idea about these links. I've read that not all Omega links have numbers etched in them. Are these an unnumbered Omega link, a knockoff, from a different watch company???

I appreciate any help and guidance.