building code was very loose back then if their was any, I think....my last house was built early 60s and had zero insulation in the external wall cavity's= just open space...
the house I now live in and rehab-ed is a 3 story cape built in 1962... and when i was opening the basement walls I found one heck of a shock...One of the center weight bearing walls that supports the 2 floors above had no base plate''' they just stood the wall studs on the concrete floor as the concrete as it was setting up n hardening... no plate.... the 2 studs on one end by my basement garage door weren't even touching the floor, they had been chewed away from insects and just soft rot from all the years....
I ended up cutting up 2x4"s to fit tight between the studs on the floor then standing studs on these mini plates and hipping it all to the existing studs, so some are 3 studs wide= 1 on each side of the old existing studs making them 3 wide, wicked strong now,