Had one just like it from about 1965. Even had old bloodstains from a muledeer liver I stuffed in the back game pocket. Gave it away about 20 years ago due to its excessive "shrinkage".Here’s our family Filson item, complete with squirrel blood stains. It was my falconer Father in law’s; now my wife wears it sometimes. It’s quality. From what I can tell, Filson has changed over the years.

Had other Filson gear of that era as well. Think the only Filson I've got left is my old tin hat.
Frankly I don't miss any of it. While it was durable I don't think it compares to the light weight, warmth, and comfort of modern synthetics and breathable shells.