That's a beauty! I believe (someone correct me if I am wrong) the white jockey wheels were introduced in the C-record era, so those would be replacements--though it appears your derailleur is unused, or practically unused.
+1 to losarchitect. The Nuovo Record RD was introduced in 1966 and the date codes on the NR RDs were introduced in 1970.
The original version had no text near the cable entry point. Version 2, introduced in '68, has the word "Patent" (without a date) stamped on the rear above the cable entry. I believe you may have one of the original versions. Reference:
http://www.velobase.com/ViewComponen...m=108&AbsPos=0
Thus, I'd say your derailleur dates from 1967-68. Nice score.