The 235 has been a 235.5 ci from the beginning.
http://chevy.oldcarmanualproject.com/shop/1941/41csm198.htm

And stayed at 235.5 ci when it went to high-pressure lubrication.
http://chevy.oldcarmanualproject.com/shop/1954truck/54ctsm0647.html

They are commonly referred to as a 235, but some non-GM parts manuals/lists refer to them as 236.

http://chevy.oldcarmanualproject.com/chevyresto/56152.htm