It sounds like you've got a mismatch, the one with the arrow should be for driving on the left and the other for driving on the right.
Drop me your address by PM and I'll send you the one I have that should match (403 with the arrow). The reflector isn't perfect but is usable. I suspect that, with a little heat, you can separate the glass from the bowl and then glue the lense onto your new (402) reflector.
Guy