Ron Guth: The 1863 Indian Head Cent has the second lowest Proof mintage of any Copper-Nickel Cent of the 1859-1864 period, yet it survives at a higher rate than dates such as the 1860 and 1861, which both have mintages more than twice that of the 1863. The result is that the 1863 Proof Cent is priced as a type coin, making it one of the most affordable dates in the series.
This generalization reverses for the Cameo and Deep Cameo Proofs, which are elusive versions, particularly in high grade. Deep Cameo Proofs can be considered extremely rare.
The finest examples certified by PCGS included a single PR67, 8 PR66CAMs, and a single PR65DCAM (the only DCAM graded by PCGS as of July 2012).