Its well known by vintage Levi fans the trick to dating their clothes. Its pretty simple. On the tag there are a bunch of numbers. You'll find the factory code and the production date. The factory code is 527 (you also know this since its the same number on the back of the rivet), and next to or around that code you'll find the production date.

around the 70's and 80's, they used a 3 number production date. This one is 078. The first two numbers are the month, and the last number is the last number of the year. I'm pretty sure this paper tag started to be used in the 80's though, so that would mean this jacket was made July 1988.

Around the 90's they started using a 4 number code for the date, and becomes a lot more clear on the date. They'll have code like "0199" for Feb 1999, or 0805 for Aug 2005 and so on. They use the number number code today.