The seat wall stones receive a new base (the actual primer), two separate colourful washes, and then a final warm brown wash. Most scenic painting is worked in various layers. It’s how they were painted back when the park opened. Really fun stuff to see!
Also if you notice, the old rocks look a bit worn and reddish-brown, with a sort of gloss sheen. This is due to people constantly sitting and leaning their hands on them. The phenomenon is jokingly referred to as “people funk” as it, well... is a result of the various human secretions wearing down the clear coat on surfaces lol.