yes they are very rare . I have quite a few doubles though. I have paid upto about £30 each for them I have only just received the last set my only real interest in buying more than one is often in search of new varieties. Some like the Flying Eagle I think there might be only about 15 known. But listen I have 4 I really don't need them all. I only bought them over from the US because I thought there were not many over in Europe. Frustrates me a little too hence starting this thread I thought it might get a few people interested.
A couple of years ago I found a small hoard of an unlisted type of Alfonso the XIII baby heads 25 pts usually what I do is donate them to the charity and sell them for them. I sold 20 of them at about £25 each simply because Pay Pal were doing a fantastic almost unbelievable offer to the charity of multiplying anything I sold times 5 in the end I managed to raise nearly £30,000 , £25,000 given by ebay and Paypal. I am always happy to sell them to other collectors for the charity. As long as I have a set I am happy. Let me know I am not too interested in making profit on them