The $1,242 Art paid for the diamond ring in December 1972 would equate to over $7,500 in February 2020.
The most recent sale of a 1870 S Seated Liberty Dollar, one of only nine known coins of this type, was at the January, 2015 Florida United Numismatists auction where it sold for $470,000. Prior to that one of the other known coins sold at a family auction in April, 2008 for $805,000.
The MSRP for a base 1968 Mustang fastback was $2,818 - which Nick notes is less than the rent on his apartment. That amount in 1968 would equate to over $21,300 in 2020. But he was making a direct comparison from the 1968 price to his 2020 rent, so his rent is over $2,818 a month.
In this episode, the current NCIS cast plays the 1972 flashback versions of the "cold case" characters. Of these characters, only two are seen to survive to the present-day investigation: Bertha (Maria Bello in 1972 and K Callan present) and Spencer(Sean Murray in 1972 and Gregory Itzin present). Each of these "1972" actors meets their respective present version at some point in the investigation. Also, Wilmer Valderrama (1972 Art) is present with the dead body of present-day Art (Joe Renteria) in the garage. Also Emily Wickersham (1972 Annie) is present with what remains of Annie in present day in the tomb.
Rocky Carroll and David McCallum are the only regular NCIS cast not to appear in the 1972 flashback scenes. In fact, Rocky Carroll does not appear in this episode at all.