Nice find, but "all original" is a stretch. Those are later derailleurs, Campagnolo shift levers, and an original PX-10 would be sporting sew-ups.
The wheels alone may explain part of the difference in "feel" from the racing bike you expected but, in general, I think it is safe to say that European racing bikes from from the sixties still had more supple geometry to accommodate the non-asphalt road construction still much in use at the time.