The Leart version more closely resembles the "round dome" lamps used on the earliest of cars. Perhaps some Euro models??? The majority were fitted with the Carello "flat tops" which are now utter hen's teeth to find......unless you find an old Alfa or Fiat dealer with some good old stock!!!
My opinion, is that if you can get good amber for front and red versions for the rear, put them in...... Don't know how they fit the original holes...........but if the job is stopped because of these parts.....chase down an old Fiat 850 Spyder to rob for it's lights!!! 
Most people, except for the brilliant eyeballs on this board would ever know the difference! It's Italian!
Oh, you could also put in the 1968 flush mount Dodge lights! These are finally repopped and were a common swap to get rid of the "bug eye" originals! My car had them....thought they were original...saw them on another car(!)....until I cleaned the old wax out of them and saw the Dodge pentastar logo!!! DOH!
Cheers!
Steve