In some cases, yes, in others, no. You can open the file in a text editor and see.
So some things in the gcode file are readable, such as the actual gcodes and the mcodes that make up the print.
But settings that are created from the slicer might be missing, unless the slicer sends that information in the comments as it generates the gcode.
Gcode from Simplify3d, for example, contains a TON of settings information in the comments of the gcode. But still, some key settings are missing, or I just cant find them?.