To answer my own question... a right handed, reverse headstock does need left handed tuners.
Amusingly, left handed tuners are interchangeably described as 'left handed' or 'xR' (where 'x' is the number on that side, but the 'R' means that as you're looking at the guitar face on, neck pointing up, then the tuners will go on the right hand side of the headstock - which is actually a better way to describe them).
Also, Mockingbird basses are bad-ass. I should put a bass on my todo list. I might need to move house first though - I don't think it'll fit on my current workbench.
To answer my own question... a right handed, reverse headstock does need left handed tuners.
Amusingly, left handed tuners are interchangeably described as 'left handed' or 'xR' (where 'x' is the number on that side, but the 'R' means that as you're looking at the guitar face on, neck pointing up, then the tuners will go on the right hand side of the headstock - which is actually a better way to describe them).
Also, Mockingbird basses are bad-ass. I should put a bass on my todo list. I might need to move house first though - I don't think it'll fit on my current workbench.