Mopar used two different types of posi units in 1969, the early Dana clutch type that used the center adjuster with the retaining pin and the other type that didn't use clutches inside of it and no center adjuster pins or retainers either. 1969 was the first year for the 489 case also but not the last year for the 741 cases so the 741 posi could be either type depending which year they where made in
On the end play use the side adjuster to barely have any end play, no more than .010, less is better than a tiny bit to much