Those A logo tuning heads are made by Gotoh. I'm not sure what year they started with the logo'ed heads, but before that, Gotoh's like this would have been the OEM heads out of the factory for an Essence.
In the early days (probably up through Distillates, maybe even Spoilers), Schaller heads would have been the standard. I don't know whether they would be the standard on a Series bass today, but they were the standard on Series into the 90's. They are more expensive than Gotohs, although many people feel the precision of the Gotohs is better.
The shaft hole diameter and position of the little positioning screw is different between Schallers & Gotohs, so, at a glance, it doesn't look like these have been changed.
David Fung