The original dimensions of a straight trap were 1 3/8"=DAC, 1 7/8" DAH.
Early skeet were 1 1/2"=DAC, 2"=DAH. (drop at comb, and heel)
But, I believe this changed at about the same time Winchester went to the Stage III trigger. I've measured a few NIB guns, both straight trap and skeet and late models. They are the very same or higher than the above straight trap measurements. This may be manufacturing tolerances, but I don't think so.