Identify gearbox

I’ve got a few spares for sale in the other section but wondered if anyone can confirm whether my gearbox is an original or from a different Reliant (if indeed there is a difference). It’s obviously been in a Bug because there’s orange paint near the gear lever.

There’s a number stamped on the top cover ‘9851’ with an ‘L’ below then inside the bell housing there is ‘20113’ and ‘ADC’.

Link to photos: we.tl/b-v9cc0nhM9I

Cheers, David