I ran across this on the bay and have the owners permission to use his photo. This is an 11AC 23 jewel movement. The owner said it has an "N1" date code stamped on it. All the information I've seen shows the 11AC movement was made between 1955 and 1958 and only in 17 jewels. The 1971 ABC parts catalog only lists the 11AC in 17 jewels. Did Bulova bring back the 11AC for an encore in 23 jewels and have you ever seen another one?