Vintage Datejust question, picture included

[orlandoboom]

Hello everyone,

I have in my collection, this vintage datejust. I am unable to discern any info from it other than it is perhaps from the early 1960's as the watches without tritium did not have "swiss" printed in the dial (correct me if i am wrong).



My questions are:

-do I have to worry about this piece not being genuine, it does not seem altered in any way?
-does anyone here know the actual "vintage," years of manufacture or whatnot?
-if there any bits of info relating to this model I would appreciate hearing for sure.

It currently does run, losing about 1 minute an hour, would you say it is worth restoring?

Please forgive my lack of knowledge, I am a bit new to vintage. I appreciate any help!

A bit of background, my late Grandfather gave me this watch after he retired from the US military, many years ago.
I wore it through High School all the way past College. I figured if he wore it during service, I can daily wear it!


Cheers!