‘Skeletonized’ watches may not be to everyone’s taste – me included in fact! – but they are nevertheless an interesting type of watch. And to be fair they make it easy to see what’s going on inside without taking anything apart 
Citizen’s first skeleton models were made in 1971, using the 76xx movement. These are essentially the 25 jewel 7290 (i.e. hacking) version of the 72xx family, with no date or day wheels and with modified plates with special finishes to enhance the see through, or see into, nature of the type. See the 72 Family Tree to see where these fit: http://homepage.ntlworld.com/stephen.netherwood/72Leopard&SevenStarFamilyTreeSecure.pdf
This movement runs at 21,600 beats per hour, and was produced for only about 3 years when it was replaced by the 8060A, running at 28,800 beats per hour. These later models can quickly be identified by the position of the Citizen logo – it was moved from being stamped on the movement itself at 9 o’clock (76xx) to being printed on the chapter ring at 6 o’clock (8060). There are no serial numbers on the skeletonized models so an exact year of production cannot be determined.
The 76xx skeletons were produced with stainless steel, gold plated or black coated cases and the movements were finished in either gold or black, and had three types of second hand design as far as I can determine. As far as I can see the main hands were of two types, one of which is lumed. Mine is a black cased model with gold plated movement, lumed main hands and red ‘lollipop’ second hand:
The stainless steel model with black coated movement can be seen in two of the above images, whilst here are examples from the 1971 catalog, which have a standard second hand and non-lumed main hands:
And two other models from the 1973 catalog with more rounded black cases, black movements, a Cosmotron type second hand and lumed main hands:
Note the original retail prices – these were quite expensive watches in their day, using good quality, accurate and reliable movements.
