Help in dating Gold Rolex

[andych]

Hi All

I have just inherited an 18crt Yellow Rolex perpetual dateajust and recently
had it cleaned and valued for insurance,the case reference numbers
and model numbers are not helping me age the watch,I have a recipt for 1956
but when I cross reference the model # I seem to get 1958,can anyone help
me verify the age of this watch.

Model #386829

case reference 6605

also according the the model # it should be white gold but is definately yellow


thx in advance

Andy