Front Servo Question

I just got done reading Carl Munroe's 727TF Transmission Handbook and have a few questions It mentions modifications to the front servo depending on whether you have an early servo or later servo. What year is the cutoff for "early/later"???

Also do you folks recommend plugging the bleed hole in a later model control load servo? When I installed the TF2 kit a year ago, it didn't mention plugging that hole, but the Carl Munroe books recommends it. What do you guys think? I'm far from a transmission guy.

Thanks!