Lehighs have a lot of tricks up their sleeves that make the architecture particularly tricky to get right. A lot of that if done wrong can make them cheek slappers. A 38" barrel can certainly work, but that micro-carbine length barrel (for a Lehigh) will contribute to more muzzle flip and more cheek slapping. Rupps are a little beefier in the cheek area and less likely to slap you than some of the others (Hawk, Moll, Long, Kuntz). but they still can if that area didn't get the proper shape and attention.
Because of this difficulty (for the original makers (there were over 150 gun makers in Lehigh County) as well as us contemporary folks) I suspect that contributed to them being a fad that faded. They really only span about 25-30 years tops. Beautiful, but trendy.