[Healeys] polarity Nash Metropolitan? (no Healey content)

[Oudesluys]

Recently I got hold of an original equipment radio for a Nash 
Metropolitan, made by Pye. It is supposedly working, however I would 
like to try it out.
I do not want to connect it up with the wrong polarity so I would like 
to ask this knowledgeable team what polarity was used in these cars as 
this car has been mentioned more than once.
I presume it is positive earth, but I just want to be sure.

Kees Oudesluijs
NL