Vintage Military Men's Green Wool Jacket Size 38 R (Medium) Field Jacket Heavy

This is a vintage men's military jacket. Unfortunately, I don't know much about it and it doesn't have much to identify it other than the size tag (38 R). It is quite heavy - over two pounds. It feels like wool and looks to have a cotton lining. There are a couple flaws, most noticeably a small hole under one pocket flap. Not sure if there was a snap or something here or if this is a moth hole. There is also an area of discoloration on the back. It's faint, but you can see it in the right light (this is shown in the last two pics). I did not try to remove it and it may be removable. I measure the chest as just over 38", shoulder to shoulder is 18-3/4", shoulder to wrist 24-1/2", and length from back of neck to bottom 23-1/2". Thanks for looking!