Or it could have been one of the very last of the 72 model year... The block was cast on 5-30-72, but if went through right away, could have made it in the last production of early June of 72 before they shut down and tooled up for 73 model year.... The VIN # just above the oil pan on the passenger side below the engine mount will tell....
Also, it looks like it has the high compression pistons with the four eyebrows on it... 72 and 73 were lower compression, and I don't think they had the 4 eyebrows... I've never torn down an original 72 or 73 340 before, but have done many 68 - 71 340 engines and those look like the early 10.5 compression pistons to me from the pictures...