If these are the kind of posts I used to seeing, they are set up with a screw jack on one of the ends to "level" the beam. Usually, the post has a no-threaded hole in it and does NOT turn, only the screw jack against it. The post should be sitting on a footing. It sounds like they poured the concrete floor over the jacking mechanism so releveling the beam will be a little less easy now. If you check the floor level and decide to re-level the beam, you will need to set up a post and floor jack next to the existing posts. I've done this before and it's important to only jack a little bit at a time, put a steel shim plate between the beam and the post top and then leave it sit for a long time to stabilize. If you don't, you may end up with cracking. I jacked up a beam about 1" over a period of about two months.