A bit of a history lesson: the orange Zapper was made in 1989 to replace the grey 1985 model as a result of a law requiring toy guns to not look like actual guns. (While most toy guns just put an orange tip at the barrel that could be removed, Nintendo took it a step further by replacing the grey grip and barrel with orange ones.)
I actually knew about that. Sure, I only know because of the N-ZAP ‘89’s description in Splatoon, but still.