This is a vintage G-1 style leather jacket. Doing some google research, came across this info:

"This USN jacket is a non-issue jacket based on the First G-1 model 55J14. As I understand, these particular jackets were made available for private purchase in Navy Exchanges as it is a non Mil Spec jacket. It was however made by a one time military contract jacket maker. It appears that some of these jackets made their way in & obvioulsy were used by service members."

"Before Zip Codes were used, Chicago 13 would have been the postal zone in Chicago."

As best I can tell this is NOT a military issue jacket. This company made military style jackets. I've included a screenshot of an advertisement from a Readers Digest from 1947 so they were making jackets since at least that era. Zip codes started being used in 1963 so it appears to date from before then. A non-military-issue jacket that was made perhaps concurrently with this actual style of military jacket.

The jacket is in very good pre-owned vintage condition. Very clean. 

The leather is smooth and supple. Zipper works smoothly. Fur lining on the collar.

Some wear on left sleeve cuff and on the bottom jacket cuff on the left (see last two photos).

The jacket has no size marking. Measurements can be seen in the photos.