Breathing Life into Vintage Rolex - Request

[Errsomeone]

All,

Request assistance on how to source an authentic rose gold pin buckle in 16mm.

Story in brief: As I am about to walk towards marriage my fiancee's family introduced a beautiful vintage piece that was her grandfather's Rolex and that she had carefully restored over time given the difficulty of parts. I am out of my depths when it comes to vintage.

The band seems to have been replaced at some point where we would like to return it to a nice tobacco shaded alligator band that would taper from 19mm at the case to 16mm at the buckle. We have gone to many ADs and Rolex themselves without any ability to bring this beautiful watch back into use.

Could anyone help me in sourcing an authentic pin buckle in rose gold at 16mm and/or genuine strap?

Attached is a pic for those who just would like to see the vintage piece itself.