Rocker shaft oil passage?

The special bolt came about sometime in the mid 1970s. All before that had the same bolts holding the shaft down. The slant 6 gets what I call "just enough" oil to the rockers to survive. It's never anything to write home about, but they do get enough. Is it totally DRY on top, or is there a little bit of an oil film? The little hot slant 6 I have in my 64 Valiant, Vixen holds 70-75 PSI hot and it gets oil to the top "good" but it doesn't soak everything down with the valve cover off.