The parking area is definitely marked with blue signs in front of the parking area spaced every few spaces. At least as far as 25 cars back, likely further.
It's marked, but as I said a dozen or so posts back, "
but if vehicles are already parked in the spots with the signs you won't see them.". Once you know where the area is it's easy to find the signs, but if you weren't aware then it can be a bit harder - especially given that the first time I parked here SpotHero had screwed up and had photos for a location in Concord rather than the right one in San Jose (to their credit, they did fix that quickly when I pointed it out)!