Aye, that's what I suspect.
I don't think there is anything more than springs and oil, but the guy that did it may have ventured a bit further and made sure that the adjusters were cleaned up to make the action a bit smoother.
I've heard a few times about the adjuster needles being left a little rough, meaning that fine adjustments weren't always possible or effective.
A clean up and smoothing out can make a difference.