Picked up a GMT Radial dial full set

[Dan S]

Originally Posted by swish77

Well, it's specific to earlier 1665s (and military Subs) when Rolex engraved the serial number on the inside of the case back AND the case. By "confirmed" I mean there is no way the case back could have been switched from another watch because the case back serial number matches the case serial number.

With every other vintage Rolex, you often don't know 100 percent whether the case back is original to the watch because it could have been swapped. Not so with earlier 1665s. (I believe after about 5.2 million Rolex stopped engraving the serial number on the inside of the case backs.)

Many thanks Aaron. I didn’t know that those case backs were engraved with the serial number at the factory. Very interesting.