Greetings Roy!
I don't know about the legality issue, but did notice that
the Porta Walls have become somewhat difficult to find.
There is one supplier that I know of for 15" Porta Walls in
the 1 3/4" whitewall width. They are available via the web
store linked below:
http://www.antiquecarparts.net/parts_are_parts.htm
I don't know if these are the width that you had in mind,
but they are the only ones that I have seen available from a
US supplier. The others have been either from Australia or
New Zeland.
Good luck with your search!
Kevin D. Allen
WBCCI/VAC #6359
1964 Overlander International/1999 GMC K2500 Suburban
1978 Argosy Minuet 6.0 Metre/1975 Cadillac Eldorado
Convertible