For all who missed Andrea's original thread on this watch, see it here:
https://omegaforums.net/threads/uncles-old-longines-watch.153566/#post-2093420
To reiterate, this is an uncommon and desirable watch. Along with the large size, this watch likely uses a caliber 15.26. Longines watches with this large (34 mm) movement are relatively uncommon, barring reference 3582. The design of the case, with its flat bezel, is also desirable. Though the condition is not perfect, the dial, hands, crown, and even crystal all seem to be correct. Another point is that the watch is quite similar to the so-called "Serbian". More information here:
http://watchexpertise.com/oldlonginespassion/Longines_Passion/the_serbian.html and
https://revolutionwatch.com/the-longines-serbian-serbo/
It is difficult to estimate the value of such a watch given the variation in condition and limited pool of comparable examples. Still, given that similarly-sized Longines with the caliber 12.68Z are selling for thousands of EUR/USD, I think that this watch could be worth around 5000 EUR/USD. If it was in perfect condition, maybe around 10,000 EUR/USD.
As
@Dan S mentioned, Longines should be able to provide information such as the exact date of the original invoice, the country that it was originally invoiced to, the reference number, order number, case material, and caliber. This is all on the "Extract from the Archives", which is free. See here:
https://www.longines.com/en-ca/certificate-of-authenticity