Complete fresh 69 340

The block was cast during the 69 model year, the 0 in the serial number indicates it went into a 70 model car. It would be date code correct for a late 69 or early 70.
How could a 1969 motor have a 0 in it if it's in a 1969 model from the factory? My 69 cuda vin is BH29P9 the last 9 indicating 1969. I've never heard of a motor with a 0 in it if it were in a 1969 car. Not saying it didn't happen, just seems impossible to explain, because a 0 would be 1970. So with that said it really wouldn't be date code correct.