Sounds like your friend knows what he is doing then, thats good.
The reason I brought it up is I have come across people before who advertise themselves as magneto specialists and who can "fully recondition" your mag but in reality all they do is dismantle them and clean them,none of the stuff that matters.
I have a bit of a thing about magneto's, whenever I buy a bike, even if it has had the maggy rebuilt and there are receipts I take the maggy off and get it rewound and a new condensor.
If the engine is worn the bike will run but will rattle and probably blow smoke.
If the carby is worn or not jetted correctly the bike will run but maybe too rich or too lean.
If the maggy is crook, the bike will not run.
The cost of a maggy overhaul is not a lot compared to the value of the bike and its nice to have bikes that start first or second kick every time, this wont happen with a crook maggy.