Layson's - 68 Barracuda Tail Light Lenses
Gee! I had the gap on the right housing and not on the left with the factory lenses and the Layson were the same. I just assumed it was a variation in the casting of the housing. I know the housing vary because I have two set of housing and they don't follow the contour of the fender the same.
The only thing I thought was odd was the gasket had an opening for an extra screw (5 instead of 4) that kept it from laying into the gasket groove on the housing properly without being trimmed.