I should learn to check my memory before posting things in public. I looked through my paper stack, and most of the boxes don't have the brightness number printed on them. You could probably dig it up for each one by searching the web, but it'd be quicker just to print and compare samples.
I have a Red River sample pack also, and it has the name of each paper printed on each sheet at the bottom. (They only do that for sample packs, of course.) In other cases, it's a good idea to keep the box.
EDIT: Oh, one more tip. Papers are always (at least, almost always) packed in the box with the printable side up. If you pull the paper out and lose track of the printable side, you can find it by slightly moistening your finger and touching each side of the sheet at the edge. The printable side will be slightly sticky.