https://reddit.com/r/typewriters/comments/1wmszod/whats_this_key_for_on_my_groma_kolibri_luxus/
- m/n (moneda nacional - aka use national currency like the Argentine peso rather than other currencies)
- o/s as oro sellado (sealed gold or gold currency); might also have been used for orden de servicio or orden de salida as service order or dispatch order respectively