Yes, that sounds like the one, robert. It's the safe on the table to your left, directly after you enter the workshop.
The clue to opening the laser locked safe can be found on a paper hidden inside the dining room safe. Did you open the dining room safe yet?
The laser safe can still be opened by trial and error, though, as I recall, even if you don't have the clue paper.
The clue was: "Less 8 nm under the upper limit of the buttercup nm."
(Buttercup = Yellow.)
Then from MaG's walkthrough:Adjusting the number to the known wave lengths of the visible portion of the spectrum on the panel displays the different colors: Violet (400-425), Indigo (426- 446), Blue (447-499), Green (500-569), Yellow (570-592), Orange (593-620) and Red.
The 3 digit number should be set to 584. The buttons to press to set are above and below the safe's display panel. You need to patient and wait for the number entries to register. Then the laser light beam will change colour.