I can't confirm they are still there, but there were Spots there in 1978.
As a 15 yr old, I had organized a tournament and the first day was fishing with a gentleman who was a member of the AmBassadeurs (his name escapes me). Towards the end of the day, he already had a nice limit and was coaching me on getting mine. With a few minutes until weigh-in, he pulled up to the lighthouse (on the channel side) and told me to throw a deep diving crankbait. First cast, I hook up with a nice bass, but when I get the fish in the boat, something doesn't look right. The fish is more football shaped than pot bellied and its mouth wasn't as big as i would have expected for a 2 lb fish. I said out loud "This doesn't look like a largemouth", at which time my "teacher" broke out in a big grin. He said "really? What do you think it is?". I had only seen largemouth before, so I said I didn't know, to which he responded "That's a spotted bass". Turns out he & a buddy had made about 2 dozen trips to Lake Perris that spring and kept bringing double limits of spots over, releasing them in the lake near the lighthouse.
I would expect the spots to have done well, Canyon Lake has a lot of depth and rip rap and at the time, was loaded with crawdads.