That is possible, but would also require some changes to the code to get the nude sprites. For just the CG's, you can actually do this yourself by navigating to 'HENRY'S_ALT_GLASSES-2.0-pc/game' (Windows might use '\') and copying the 'resource1.rpa' file. Name this copied version 'resource3.rpa'. Move this into 'Dragon Island/game' so that you have three resource files there.
Do note that this will also overwrite some parts of the main menu making it a bit harder to see the options. Simply delete 'resource3.rpa' if an actual mod is made.