I'm building a Kuntz Lehigh, but keyed and estrucheoned rather than pinned. I placed my estrucheon plates at the midway point between the front RR pipe, and the nose cap. Yes, in this one the nose cap is 1 1/2". If you poke around the Lehigh / Bethlehem school some more, you will find there is great variation within it regarding such things.
Because you are building a pinned gun, the pin holes aren't really a decorative feature the way plates are. There are good structural reasons for having it as far forward as you can. So long as it doesn't interfere with your pipe placement, I wouldn't worry about it.