FWIW - I don’t know if 69 is different from 1970 BUT- I have a unmolested 6,000 mile 1970 Z28 LT1 motor , that has never been apart ( except for taking valve covers off ) , and it has a 4 hole gasket on passenger side and the 3 hole gasket on drivers side. I had old NOS GM gasket kit before and it had 1- 4 hole gasket and 1 -3 hole gasket.
I was under the impression that the 4 hole gskts were generic type that were supplied by rebuilders?
I’ve been trimming the extra hole off for years in all our restorations.
Maybe James or Kurt will comment?
Hope this helps.
Mike