In the Version 2 of the Spring 2010 scan book these items have two scan bars. They're designated as "Dark Print" or "Light Print." Print, in this instance, refers to the item itself, the print on the frame or the clock. For example if someone wanted to have lighter text on the black ZALR01 frame (black and white print) they would scan "Dark Print" because the item itself is dark and the font would be set to only engrave through the paper giving it a lighter/white appearance. If they needed to engrave the light plaque (sepia tone style), they would scan "Light Print" so the settings would engrave through the paper giving it a darker/brown appearance. In the original version their is only one bar code for each product and they are set to engrave that product accordingly.

So, to Recap:
Light Print = Brown text (meant to be put on a white/light-colored item.)
Dark Print = White text (meant to be put on a black/dark-colored item.)