The norm for most of the year is like 2 days to a week. I have seen a couple that were same day! I had one that was cast the 4th and assembled the 5th of the same month.
However, there seem to be some anomolies in the late May to August 69 time frame. Normally, it would be a slow down for engine and transmission plants, because the car assembly plants would be tooling up for the new model year. Norwood just forged ahead because of extended Camaro production. Almost all the first week of Aug cars got some May dated components, and some even got some April components. Very few Muncies dated June or July. I looked at a couple of first week August Z's that were built within a day, and one had a June built motor, the other a very late July motor.
Speaking of dates, I have never seen a June or July of 69 YH ralley wheel.