PVC Mudguard Piping or Welting in Australia 1948

[ProfessorQ]

This is a general question regarding pvc piping. I believe my 1952 Holden originally had a textured piping which consisted of a vinyl cloth over a former. PVC extrusion did not start in Australia until after 1950 and most cars (early Holdens)  these days have the smooth PVC fitted after restoration. So my question is:

If PVC was not available in Australia until after 1950, was it possible that it had been imported, perhaps from the US, or is it most likely that the textured piping is correct?

I assume welting was used on GM cars  of the era and wonder what type was used in the years from 1948 through to about 1953?