Hemi valve cover marking question

I am restoring a 68 Hemi GTX 4-speed. Can anyone tell me what numbers were on the valve covers and why, thanks.

I am not sure what actual number was there, but I believe if had to do with the transmission type. So a stick car may have notheing or a 0, and the automatic have a number corresponding to the code in the build sheet. At least that was what I read a long time ago.

for ya'.