The 144 bcd cranks came out in 1968, not 1966, though they might have been available on a limited basis earlier. And while the Record rear was available until 1973, there's little chance that that bike came with 144 bcd cranks - a top-tier model like the Roma would almost certainly have switched to the Nuovo Record rear derailleur by the time the 144 bcd cranks were widely available. The other component clues all point to 1960's - and I'll bet dollars to donuts that the Record front derailleur on that bike has the integral cable stop that marks it as a 60's model. The black backing plates on the shifters point to pre-1970. Also, checking the hub locknuts as suggested is a pretty good idea, as well as checking to see if the hubs say "Record" on them. Also, by the early 70's Legnanos no longer came with the distinctive seatpost clamp bolt forward of the seattube. The overwhelming liklihood is that that bike would have come with the 151 bcd cranks.