I did find a gettyimage photo labelled as a "sukhoi-su-33-fighter-aircraft-on-a-mission-to-carry-out-news-photo" with R-77s. However its most probably an Su-35 in Syria since it doesn't have canards and has a long tail.
Unless its very simple and cheap to configure the Su-33 to carry R-77s (as in just new launch shoes and make the weapons control system treat it like R-27T? maybe?) I don't think the Russian navy is going to modify their Su-33s to do so because they have just gotten a bunch of brand new MiG-29Ks which have them while their Sea-Flankers are a bunch 30 year old airframes.
But thats just my opinion. Maybe I'm wrong.