As a perhaps useful side note, and assuming you have an L400 that just needs new innards/repair:
When I got my Trillium
way back when I didn't know/think there was anything special about the (next size up) Bargman doorlock, which didn't work. In my blessed state of ignorance I took it out and to an oldtimey locksmith with a shop full of parts...He fixed the innards and supplied me with new keys cut on original Bargman blanks, and as I recall the whole thing cost me around twenty bucks or so.
Point is, if you live in an area where there's a locksmith shop that's been around for years you might take yours to them and try your luck.
But don't start right off by telling them how "rare" the darn things are or you might find yourself paying "rare thing" prices!