If you want the exact mapping of the N64, you need to edit yourself the buttons and switch to a custom config. What you need is :
edit the files in /recalbox/share/configs/mupen (or mupen64 or mupen64plus, i never remember) add in the recalbox.conf and add at the bottom (or wheverever else) n64.configfile=dummy so that the files you edited won't be overwrittenThis will be slightly easier in Recalbox 4.1