I agree with Grizz. If you're talking about using a product like Marco rock you should be fine. In fact, if you're only going to be doing FOWLR, you probably don't even need any live rock at all unless there's something specific you want beyond filtration that comes with it. You could do 100% dry rock, toss in a bunch of raw shrimp and a couple vials of Start-up from Prodibio and in a couple of weeks your rocks would be 'live' enough with nitrifying bacteria to support a small school of anthias. After that, those rocks will behave just like any other kind of aquarium filter; the bacteria population will grow to match the size of the food source, so if you added fish slowly, you'd likely never have a problem.
Of course you wouldn't have anything else in your tank except rock (and I assume sand), bacteria, and fish, so if you wanted more biodiversity than that you'd need to add live rock, sand from someone else's tank, or some of the live pod cultures you can get these days. However, with the addition of live rock or sand from someone else's tank comes the ever present risk of introducing all sorts of nuisance species of algae that your angels might not eat. It would also be a lot cheaper.
But the moral of the story, if your goal is only to provide filtration to remove ammonia and nitrite, buying live rocks isn't necessary at all. You could even just add the raw shrimp all by themselves and the dry rock will eventually cycle (nitrifying bacteria seem to be able to appear magically out of the ether whenever there's a food source for them), it just speeds it up to a time scale that's comparable to letting live rock cure when you add a product like Prodi-bio, or this stuff:
https://drtimsaquatics.3dcartstores....ria-_p_50.html