They’ve replaced the distributor cap (and something else - maybe plug wires??) - anyway it was a cheap and quick fix … yay!
Thanks Tuckerfan for a mechanical explanation that I actually understand! You should win a prize or somethin’ …
No it doesn’t.
Well, if the cap is arcing internally it could send spark to an adjacent terminal at the wrong time, but that would be rectified with a new cap. Distributor cap failures do not affect the timing setting, nor does cap replacement. There is no need to even check, much less adjust, ignition timing relative to distributor cap issues.