If the rock was really cured, then you'd see no die off from the rock (which would create ammonia), so in theory your tank might be cycled.
BUT... I like to see something - anything - that tells me things are good. I'd throw in a pinch of fish food, or the cocktail shrimp, and see if you get any ammonia. If you do, then you need to cycle. If no ammonia, but instead you see nitrates after a week or so, then it means you have the good bacteria on your rocks processing that waste and you're good to go.
Stability is just "bottled bacteria" and you'll find debates all over the web as to whether or not these products work. While they might serve as a temporary "boost" to the tank, in my opinion, they don't really populate your tank with a good population of bacteria. Most of those products tell you to keep using their product with every water change. If you just cycle your tank normally, it may take a month or two longer, but you'll never be in doubt that your tank cycled and you'll never have to add any bacteria in a bottle with every water change.