It is real!
http://sewingchest.co.uk/pdf/p19-Interfacing.pdf
Cotton woven with PVC dot resin
is what is commonly called Solidot and
is probably one of the oldest interfacings
still used today.
Woo!!! I am very lucky to have just enough for my Sunburst as what I have I cannot find any more. What I have is a very well woven cotton fabric of a complex weave and a very distinct regular series of opaque dots. The closest I can find is in fact labeled as anti-skid fabric. And yeah. Very similar. But it’s annoying it cannot be found any more.
But I can’t very much info about who produced the stuff and why I cannot find any since about 2010.