Octagons are 22" (same as ZG) with a straight stock and the end cap forearm. Micro groove barrels and supposedly made only in 1973, however mine and a few others that I have heard of, is on a '72 frame.
Minty ones are bringing crazy money- upwards from a grand. (That would not buy mine.). I forget the exact number made, but it was less than 2500. Jack
"Do not blame Caesar, blame the people...who have...rejoiced in their loss of freedom....Blame the people who hail him when he speaks of the 'new, wonderful, good, society'...to mean ,..living fatly at the expense of the industrious." Cicero