I don't know how you have your l/s stored but if are willing to put the effort into it, you can make your own mini l/s swatch/labels. ie. dab a swatch of your l/s onto a small piece of paper (you can buy white dot stickers) and then just tap over it with clear tape, this will make sure you don't smudge l/s all over the place. You can place these swatches on your traincase, storage box or even on the side of your l/s itself just somewhere visible where you can see it clearly and easily.
Hope this helps and I hope I'm making sense
haha I just read the post above, seems like much less work then my idea