Vin Numbers on 1969 '383'

Sorry I forgot to add this to earlier post. This engine only has an 11 sequence letter/number Vin on the oil pan rail. Has anyone ever seen this? There are no weakly stamped spaces for additional numbers. The first 7 are there identifying make/model/engine/year/plant.....but only 4 numbers for the car build sequence. Anyone ever heard of this? Thanks.