Should there be a grounding strap from the engine to the body?

If you have noise in the stereo that you can't make go away or if some of the electronics that you've added to the car (that weren't there OE) misbehave or flat don't work on occasion it's likely the fault of a ground loop. Have to keep in mind that how it was built back then did not include modern electronics, and those are susceptible to noise from ground loops. Instead of looking how it was done back then, look at how it is done now on modern vehicles.

If it's a true restoration, then how it was done then is absolutely how it needs to be done.

If not, then how it's done now is more relevant.