Very likely^, and the Campy 1010 DO has a hole for the "Gran Sport" model Campy RD spring, that DO was introduced in the late 1950s but remained in use for a long run. Nice that the PO didn't "drew" off the RD hanger or any of the braze-ons, plus left the original paint and decals! I hope you bring it back to closer to it's former glory, nice score!
EDIT: looking again that DO may be a stamped model 1010/1, but clearly has the spring hole for the RD so maybe dates from the '60s to the '70s