While GM did not push the 1968 Z28 with much of a marketing effort, any dealership that wanted to order one was, for the most part, able to get it, unlike the 1967 Z28s.
It wouldn't make much sense for Berger to order an SS Camaro load it up (ie: disk brakes) and swap in a 302. The car wouldn't be equiped with the 15x6 DF Rally Wheels and the tac if ordered would not be correct.( not all 68 Z28s received the correct tac.)
I do not know if Berger was building Super Cars prior to 1969.I have never seen a Car or info to support this, but list members will correct me if I am wrong
They did however order and sell COPO Camaros in 1969. The number of Camaros ordered ranges between 35 and 50 depending on who you speak to.
There are no official dealer Documents (per the Bergers)to substantiate total production.