Rolex

i was offered for purchase a GMT Master II Pepsi. The serial number is from the T series. The clasp on the bracket is a flip clasp without a lock. This seems unusual to me. Does anyone know if these clasps were used by Rolex on GMTs of this vintage, or ma...  

gmtmasterhistory.com seemed to confirm that this bracelet was one of three being used on GMTs at the time.

It is from circa 1989-90 but I don’t recall the serial number right now