I can't comment on the order in which the PP3 and ESB were painted, but for the most noticeable differences:
The PP3 has an additional yellow kill stripe.
The PP3 has an additional thin black vertical line on the upper RF ear.
The "cat scratch" area is significantly different.
The PP3 has some pale chalk-like weathering, most noticeably a downward sloping streak on the lower right mandible.
There are other differences in the damage patterns, but those listed above are (IMO) the most prominent.
These differences might not be readily apparent to a casual fan, but to the detail junkies the differences are easily identifiable.
They are what caused me to cancel my MR helmet order. It was marketed as ESB, but it used a combination of features from the PP3 and ESB helmets. :wacko