Just in case other lefties are reading this and sweating............... I'm a leftie, have been all my life
and I have one transitional 149 with a 50s OBB nib that is as sweet as a nut........and a similarly aged 146 with OBB nib - also a great writer!
Do not despair if you are thinking of an OBB - have faith - order one - buy one - steal one - but get one!!!