I don't know the worth, but I have one from the same year with a full Chorus group and it rides like a dream. Good enough for Sean Kelly, good enough for me!
if this is for the splined, 1950's crank, I was looking as well and then a bunch popped up in a row on Ebay in the US. I ended up using a gear puller from an auto mechanic once and it worked quite well. Easier on the left side than the right!
Good luck
two words: Yellow Spot!