Real 550 cord has a core of 7 strands that aren't twisted or braided or anything, they just lay there parallel. I haven't seen anything else with that kind of core. The breaking strength will definitely be on the label.
There's a great variety of stuff sold as "parachute cord" or "parachute-style" cord.... The worst of it has a core of unidentified recycled fibers, mixed cotton, polyester, whatever they could get cheap, and who knows how strong it is. Even the worst of it isn't useless, of course; in fact it's fine for many purposes; just don't use it where you need strength.