One possible approach: the .smd format (the big part of it, after the initial 50 or so lines) would be readable by Excel as a text-delimited spreadsheet. This would allow you to rig one version, export to .smd, import into Excel, yoink out the columns containing UV information; export the next one, import that to Excel, pull only the UV-coords columns, and swap that into the first one. Copy-paste into .smd file, possibly massage whitespace, and you should be good to go.