Yes they were, but not in the 1960s. I helped renovate an ancient house in Atlanta that was built around 1880. The 2X4s were made of solid oak and were not planed smooth. We could pull nails out of those, had to saw the off or break them. We couldn't pound nails in either unless we pre-drilled. The electrical wiring was bare copper, phases run separately using porcelain "knob and tubing".
Today's 2X4s are originally sawed to exactly 2X4, then generously planed smooth.
MY Dad bought a farm that was built at the turn of 1900 in 1947.
The house was solid OAK -—AS was the barn...and other outbuildings.
THEN HE GOT DIVORCED FROM mother & HE got the barn & the outbuildings, etc. ABOUT 1963.
HE remodeled the ‘hog house/granary’ into a 2000 sq ft house.
THE OAK BEAMS & EVERYTHING ELSE WAS SOLID-—AND WELL PRESERVED. HE LITERALLY HAD TO DRILL PILOT HOLES FOR EVERY SINGLE NAIL HE USED.
I inherited the building & grounds in 1980. Sold it to my youngest brother in 1998. HE still has it. Now worth well over $500,000. 1.75 acres of ground.