Complete novice needs help with gcode file

A friend of mine was given a .gcode file be a maker for a triangular gauge. I know next to nothing about creating objects to print or the files associated with them, but after a couple hours of research, it appears that .gcode files are not the print file I would need, but a config file used by the printer. That said, I did load the file into a gcode viewer and it does show the object. At this point, I just want to convert or recreate this file into an .stl so I can get it printed. Could any one assist with info, advice, or even taking on the project?

I would attach the file, but apparently I need three posts before I can add attachments or post links

STL files are very dumb. They require significant work to back annotate it to the point of having an intelligent STP file.

What is in the gcode, maybe, is a printer config information that generated the STL file. You can print the file but you may need to splice it into a known profile that your firmware will accept.