Also there are NO legitimate variations of the Janitor in a Slum puzzle, there are no yellow versions.
Each of the original 120 sets came with one puzzle, no extra puzzles were printed. Probably no more than 10 sets have been broken up, so there should not be more than a small handful of puzzles available without the stickers.
As a rare item, the legitimate puzzles have become quite valuable. Forgeries ruin things for everybody, so it is a major violation of the community's trust that should be taken quite seriously.
So far no forgeries have been found that are not easily distinguishable. Quality on forgeries is much lower.
Only what is listed on the LW1 page and the list of production materials for LW1 are legitimate. No other items you might see out there should be considered valid.
If we work together our special little hobby will be able to maintain its integrity in spite of the selfish elements.