It appears in the mid 50's Rolex reset their serial number database.

How do you tell the difference?

serial #1283748

Several online sources say 1959

Others say 1966 (after the reset)

Two local, Rolex dealers say 1959.

It's an original, stainless Datejust on the right

One on the left is a 1972

so, no one here knows?  

https://www.bobswatches.com/rolex-serial-numbers

1966

Thanks, but....

My question was how can you tell if it's pre or post reset.

Do you think the bracelet is original? What’s the date code on it?

1959 because of the hands.

But also if you could post up the model number.  
It is located on the case between the lugs on the 12 o clock side of case.

This will give you the answer.

Or open it & movement number. Can give be you a rough, but better idea of the time frame

thanks

model #1603

the hands have never seemed to match those of 1966 watches I've searched online.

I'll have a local jeweler open it to determine the movement number.

Yep.

Should sport a 1560 movement.

The members on the Rolex Forum or Watchuseek will be able to get you a sure answer fairly quickly.

ETA: I think it’s early ‘60s and both of those numbers are wrong. Or it’s ‘66 with replacement hands of an earlier vintage. I am not an expert. Just a dude who has looked at a ton of vintage DJs, and have owned a few. Parts migrate and are changed over time. Do you know it’s ownership history? That may help, and if you can determine if it’s ever been serviced by Rolex or a local watchmaker, etc.

both of which numbers are wrong?

serial numbers and models numbers are on the cases

bought by my late uncle, not certain the year he acquired it

yes, regularly serviced by authorized Rolex watchmaker

The year(s) of production. I said that based off of features and because I don’t think the 1603 model was yet released in ‘59. If it was serviced by Rolex or a Rolex accredited shop that may explain the original parts that don’t quite line up with the dates you mentioned, hence my remark about the parts migration. I’m now beginning to lean toward it being a ‘66 and the watchmaker offered him new NOS hands he was sitting on. As mentioned, the movement ID will help, but that too could have been changed at some point. Also, the 1570 was introduced in ‘65 so leftover movements may have been used into ‘66. Are you able to “hack” it, ie the second hand stops when you set the time? That’s an easy way to differentiate between 1560 and 70 movements. Lastly, photos of the bracelet markings and numbers may help yoy narrow down a date range but keep in mind that those  were often replaced as well. The commonality of replacement parts on these watches is one of the reasons that DJs are sometimes hard to date. Hopefully someone with more knowledge than I have will chime in and help you out. Again, a Rolex expert/historian will be able to tell you more. Consider asking the question on a dedicated watch forum. Some of those guys really know their stuff.

Beautiful watch and a nice family heirloom. Enjoy it!

ETA: Turns out the 16XX series debuted in ‘59, so it could be from then. If so, I think the dial has been replaced. Trying to find examples of the earliest 1603s online is proving harder than I would have guessed…

Confirmed 1966 and 1972

Hands on the '66 may or may not have been changed.

Thanks