In the stream commentary for some of competitive Geoguessr I've watched, they definitely often mention the color and shape of the car (visible edges, shadow, reflections), so I assume pro players know which cars were used where very well.
There is a lot of "legitimate" knowledge. With just a street you have the type of road surface, its condition, the type of road markings, the bollards, and the type of soil and vegetation next to the road, as well as the presence and type of power poles next to the road, to name a few. But there is also a lot of information leakage from the way google takes streetview footage.
Nigeria and Tunisia have follow cars. Senegal, Montenegro and Albania have large rifts in the sky where the panorama stitching software did a poor job. Some parts of Russia had recent forest fires and are very smokey. One road in Turkey is in absurdly thick fog. The list is endless, which is why it's so fun!
When that happens, is there a wild flurry of activity in the GeoGuessr community as players race to figure out the latest patterns?
However every once in a while you'll get huge updates - new countries getting coverage, or a country with older coverage getting new camera generation coverage, etc. And yes, the community watches for these updates and very quickly they try to figure out the implications. It's a huge deal when major coverage changes.
If you want an example of this, zi8gzag (one of the best known in the community) put out a video about a major Street View update not long ago:
https://www.youtube.com/watch?v=XLETln6ZatE
The community is very tuned into Google's street view plans - see Rainbolt's video talking to the Google street view team a few weeks back:
Copyright year and camera gen is a big thing in some countries too.
Obviously they can still figure out a lot without all that and NMPZ obviates aspects of it (you can't hide camera gens, copyright and season and there are often still traces of the car in some manner). It's definitely not all 'meta' but to be competitive at that level you really do need to be using it. I think Gingey is the only world league player who doesn't use car meta.
Even as a fairly good but nowhere near pro player, it's weird how I associate particular places with particular types of weather. I think if saw Almaty in the summer for example it would feel very weird. I've decided not to deliberately learn car meta but still picked up quite a lot without trying and your 'vibe' of a place can certainly include camera gen.