Certainly!!! There are several ways to do this.
A) Via the AstroCenter Dashboard: AstroPrint syncs your files across devices. If you upload a file to your AstroCenter Dashboard, it is immediately accessible from your AstroBox, as well as from your AstroPrint Mobile app. To upload the GCODE through your AstroCenter Dashboard:
Login at AstroPrint.com, click on "Design Library." From there you can either 1) Drag the files you want to upload onto the page. Or, 2) Click the Green Up-Arrow beside "Print Files" (in the right hand column). The will allow you to upload GCODE or X3G files.
Once uploaded, go to your AstroBox Touch and make sure it is logged into the same AstroPrint account you used above. The print file should now be accessible right from your AstroBox, under "Cloud Files."
b) Via Thumbdrive: Easy Peasy. Put your GCODE on a thumbdrive, insert it in one of the AstroBox Touch's spare USB ports. Your GCODE (or X3G) should now be available on the AstroBox Touch under "External Files."