Yes I believe there are a few which have been changed to galvanised after they left the factory, but I referred to those built by ReliantGeraint SabreGTCse5 wrote: ↑Sat Jun 16, 2018 7:25 am+3
I have restored 3 steel GTC's replacing one on a new galvanised chassis and had two chassis's dipped..... unfortunately their details were on a lap top than went pop.
For example, my 1985 SS1 1300 was rebuilt on a galvanized chassis when just over 3 years old, due to accident damage. So there is also a number of possibilities to find galvanized chassis amongst the rest of the GTC production.
My suggestion to the original poster would be to look carefully at the chassis condition, and if after chassis #372, it should be galvanized.