You can click on Save Parameters in GSPPlot which will create a PRM file containing all your settings including panels. This, however, does not work it you have gotten the file into GSPPlot using the Output Selected command in Composer. In other words, it must match the complete saved PLT file or the PRM file connot relate properly to the saved file.
The other way to go is to save a spool file (SPL) from GSPPlot. This will run on its own when called up in the future but will not allow you to view or change anything about it.