Leather for a Vintage MC Jacket Repro

[Deleted member 16736]

I'm having a repro made of a late 1930's motorcycle jacket. The original was in horsehide of medium weight. My choices are Horween chrome-tanned 2.75-3 oz. horsehide or Japanese veg-tanned 3.75 oz. cowhide. The cowhide is very thick and well-made, but I vastly prefer horsehide. My question is, will a horsehide of 2.75-3 oz. weight be period-correct for an MC jacket of the late 1930's? I don't have a picture of the jacket, but it's an aviator-style motorcycle jacket. Any opinions would be appreciated, since I don't know a lot about vintage MC jackets. Thank you.