If you can locate a real old fashioned locksmith, they can likely make you a key. I did this with an MGB - the locksmith inserted an uncut key, wiggled it a bit, studied it with his loupes, filed it, tested it, filed it a little more and in about 10-15 minutes he had working key. Then he could simply copy that for a few spares. The doors, trunk lock & glove box all use the same key (if they are original...).
Alternatively, I have read that there might be a code imprinted on the lock cylinders. If so, you can get a key cut to that code.
Keys4Classics might be able to do this for you. Don't be dismayed that they are in Australia. I had some keys made by emailing them a close up photo. I had the new keys (worked perfectly) in less than 2 weeks via Airmail letter.