^^ I am not sure when the cutoff was. There is a way to inspect them to tell the difference. IIRC the head of the bolt that is captured in the rod is shaped differently. I found a picture of it in one of the Bentleys of the period.
For quick reference, all hydraulic head/blocks will have stretch bolts on the head bolts.
Connecting rod bolts get re-used most times.
Probably good for 3-4 retorques.