What year would that have been, JM ?
Can't find any mention of that in the records.
And, Nortons had had several previous encounters of having machines not finish from using untried technology,
so I'd find it unlikely they would have fallen for that again again....
There must be nickel bronzes and nickel bronzes too, plunger dommie frames are routinely repaired with nickel bronze these days. I have one such example myself, and although it hasn't won any IoM TT races, its still hanging together...