I just looked at both lamps, and there are no labels etched or engraved anywhere on the lamp. When I purchased these, I didn't at all think of them as collectibles that I would one day sell -- I do seem to remember small paper labels that were stuck to each of the lamps, and taking those off before I carefully wrapped and stored them. Ah - if only I kept them on there! At the time, they didn't seem important at all... In fact, I never would have thought to leave them on, as they weren't at all attractive to me - only informative. I thought perhaps they were just identifiers for importing/exporting purposes... I remembered these pieces of paper when I saw a very tiny bit of what remained from where it was stuck on the lamps near each label when I searched for the etching/engraving marks as you suggested.
You have no idea how grateful I am to all of you for all your expertise and guidance with this! As a very small token of thanks, I'm enclosing a link about a sweet story of gratitude... Enjoy! http://www.youtube.com/watch?v=xgOyTNtsWyY