Yeah quarter lined like this seems to be what's going on with the jacket on screen.
View attachment 619421
Like that, because the body has no lining but the sleeves don't get stuck and you can see a flash of lining when Finn is pointing at the Millennium Falcon as he says "we can't outrun them" and stuff.
You're definitely making a good argument though haha, I think goat and lamb fall very similarly but this up close picture shows texture that screams goat to me and shows the strap is painted and therefore I figure the leather section would be painted too
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I feel like you
almost could talk me into this, but the goat skin instead of lamb skin is important to me because at least from my experience with leather, a good lamb skin will last you ten years if you're lucky, but a good goatskin... That you'll be writing into your will.