GMT Master II 'Pepsi' questions

[CJamesG]

Hi, first post on here but have been browsing for a while.

I am looking at buying a GMT Master II with the 'Pepsi' bezel, I have found a 2001 model in a shop through a friend so I am happy all is legit.

This will be my first Rolex and first pre owned watch so is there any due diligence I need to do before handing over the money?

I have seen a few for sale that mention they originally had a black bezel but had it swapped out for either a 'Pepsi' or 'coke' coloured one. Is there any value in having a watch that came with the different coloured bezel from new? And is there any way of telling from the serial number?

Sorry if they are silly questions but couldnt find any answers from searching the web or the forum.

Looking forward to owning my first Rolex!