That is interesting dbtk, Sacco has commented a lot on past work ..he also thinks the 600 had too much chrome on it.
The tailfins were out-of-date by the time they went into production, as you said.
By 1961, Lincoln was leading the way in automotive design with the slab-sided Continental.
1963 Lincoln Continental limousine. 
Rolls-Royce also had it's special Mulliner versions of the Silver Cloud coupé designed by the Norwegian, Vilhelm Koren ...it was a lot more modern than the standard version.
Standard version Silver Cloud ...looking quite old-fashioned by comparison.
The 600 also was right up-to-date with it's styling.
