This is an R serial 16610- the earliest model from 1988. It has the 25-295-C2 crystal, no LEC, no AR. This watch has the same dial as you have- I refer to it as the MK1. This dial was used during that time period in the 16800, 168000 and the 16610.
The case is your next most important item. A ST3135 case with lugholes would be good or a TC case with the lugholes drilled would be another possibility. I don't know if a BP or JF would work (you'd still have to drill the lugholes.) Until you get the case squared away, I'd just get a Clark crystal- you can always upgrade later.
A flat 4 bezel insert would also be period correct. Good luck