i agree with byron re the ugly stamps...different plants did have different fonts and some stuff wore out..the first 0 that has been stmaped is in line but appears to be only half stamped..if it got to the end of the line and a human restamped it then that could be your answer..
i owned a 70 pontiac transam a few years back..pontiacs have a matching vin number to block number..this vin number is stamped on the engine down low in tiny stamps.2 of the numbers were xd out and the correct stamped above..this was common for pontiac to do...
someone needs to start taking pictures of all chassis numbers on hq to wb to look at fonts and stamping errors..we do know holden made mistakes.

maybe i should do that when i get a chance?