@Dragster
Of course the original OS1.3 icons would look better with that theme, but you know icon handling on all Amiga(-ish) OS' - it would be a pain in the a** to change them back and forth, BUT:
If someone had really enough spare time, he could replace all old-style OS icons with the OS1.3 ones and put the icon data for the 32Bit-icons back in place - OS4.1 still has the fallback pictures for 4-colour Workbenches in-build. So switching "True-Color" icons in Prefs OFF would lead to the old OS1.3 icon look. Anyone? ;-)