matthewking
297
11 made, various arrangements
Hi Dylan,
Well, you've picked quite the reference to zero in on - the ultimate vintage AP to be sure.
It is my understanding that there were only eleven 5516s made, all in 1957. Not all of them featured a leap-year. Of those that did, six have the moonphase at 6 and three have the moonphase at 12. The watch you show from M Friedman is certainly a 5516.
The watch sold by Christies is actually a precursor to the 5516. Three of these were made, in 1955, and they had no reference # at all. As you may guess, the 5516 is a direct descendent from this (basically unique) predecessor. Both use the same base movement though - this "no reference 5516" ticks on a Valjoux13 VZSS while the 5516 runs on a slightly modified Valjoux13 VZSSQ.
To say that the Christies' watch is rare would be a massive understatement. These are virtually unique, and I believe only 2 are currently known to still exist.
I hope this helps,
Matt