eelpout, what is your serial number?

i have a model 775a witha super choke that dials to varying choke size with 4 word abreviated positions of choke and a line. . . screwed all the way down is full and as you screw the choke out it goes thru modified, improved, and cylander. . what i do not know is where to line the abreviation and line? with the sight bead? the reason i ask your serial number, i am trying to date mine.. . mine is 258694