I presume you're referring to a Paulson LCV or SCV mold and not the RHC or C&J hat & cane mold, correct?
Also, there could be slight variations in molds - a millimeter or two here and there - based on the specific mold used to create the various chips out there. In speaking with David Spragg this weekend, he indicated that they've have or have had hundreds of hat & cane molds in use, and some clearly have slight variations from one another.
Anywho, I mention all this just because I'm not sure how precise you're looking to be with your project, but to encourage you to allow some tolerance in measurements. We can't be too much more picky than Paulson/GPI, and they don't even check to make sure the same mold is used on each side of a chip.