They must be, since I bought one for myself less than 6 months ago. Probably more like 4, actually. Talked to Leica US in New Jersey and they said it was no problem at all. I'm using a bulb marked EFY and am trucking along happily.
Amazingly, they could also supply me with a new, updated-model (double condenser) mixing box if I wanted, though when I did illumination checks on my enlarger with the old-style condenser, I found only 1/6 stop of difference in illumination between the center and edges, so I opted to forgo the new box.
Thanks, Patrick. I'm in the UK so I've emailed Leica and am waiting for a reply. Good to know that that the adapters are still available - even if it turns out to be on your side of the pond.