The Key from any locking Hammond from 1936-1965 will work, they are all the same! If you can find another Hammond owner, borrow. If not, any petty thief with a hair pin can get in: Have you converted any lately?
Locking organs discourages adventurous future organists, and thus instruments sit unused and unappreciated.
NYCF is right if it is a B-3. It looks too new to be a prewar AB or BC, which leaves BV, B2 and B3 possibilities. Once your burglar gets it open, if there are 7 white rocker tabs beside the keyboard, you have hit B3 gold. If there are 3 tabs, you have B2 silver, and with no white tabs, you get the bronze, it is a BV. The B2 is worth less and the BV a lot less. Though in fact they all sound as good, but the vagaries of fashon have decreed B3s the top. The Leslie speaker is what makes the difference, and whether a 122 or 145 it could bring up to 2k with connectors all by itself.
Lee
If you can keep your head
when all about you are losing theirs
and blaming it on you
Its just possible you haven't grasped the situation.