D-reg Daytona with engraved rehaut ?

[BASSETHOUNDS]

I had to pick up a business parter at Barcelona airport this afternoon but as he missed his connection flight due to strikes at Iberia I had about 4 hours to kill . I decided to go downtown and shop around for the SS GMTIIc I'm after .
I was at a upmarket secondhand shop that sells high end watches i.e. Rolex .
I had a look at a very emblematic variety of Daytona ( I dare not speak its name ) anyway I was very surprised to see it has the rehaut engraved with a D reg serial number . I know of a friend who has a Z reg Daytona and his rehaut is not engraved like mine ( F-reg ) When did Rolex start engraving the rehaut on Daytona's ? I cannot believe the watch I saw is fake , I can't see how you could copy a thing like that . The shop is very reputable and experienced .