I've started this post to help our esteemed colleague@Sogeha , the hypothesis is whether the JF 16610LV can be used as a base for a 16800 franken. On to the comparative photos...
This 16800 is very aged, the bezel notches are smoother than the 16610 due to wear over time:
The rehaut is the same depth, making a sanded and polished 16610 rehaut a legit option.
The 16800 bracelet is slightly more polished due to wear over time.
The SELs