Hi, Cook17,
I just label with a marking pen on the area that will be cut off when opening the vac-pack.
No, you don't need to add any preservatives, the meat will keep just fine in the refrigerator for a few days or in the freezer for longer periods of time. I usually date everything I put in the freezer.
With ribs, depending on the bones, you may have to cover the ends with paper towel "socks" to keep them from puncturing the vacuum bag.
Normally, ribs don't last long enough around here to vac-pack them. If there's any leftovers, I usually wrap in saran then foil.
To reheat, just place in the oven at about 250* for an hour or so. That's it. They usually come out great.