There is another way of dating a genuine Lister CS engine. This information has been copied and pasted from the UK Lister CSOG and it goes like this.
You can always look on the crankcase, on the opposite side to the
injection pump, right above the crankshaft bearing housing you will
find foundry casting marks telling you the month and year that it was
cast. It will be something like 15-A-53
Where 15 is the day or batch number, A is the month, where A=Jan,
B=Feb etc and 53 is the year.
Mick