A Question For Jefferson Aficionados

it would be helpful to know what year of nickels you are asking about.

For 1965, 1966 and 1967 the mint made both MS and SMS nickels.

1994 and 1997 the mint made both SP and SMS nickels.

As posted ... I think PCGS did label these differently in the past.

For 1965, 1966 and 1967

The Philadelphia mint made both business strike coins for circulation
and Special mint sets (SMS) for collectors.

If the Jefferson was sent in today, and it is a uncirculated
coin, that was made for circulation, PCGS should grade it
something like this. (depending on grade)

1965 5c
PCGS MS65

If the coin came from a Special Mint Set (SMS)

1965 5c
PCGS SP65
SMS

Edit - I should mention that in 1965, 1966 and 1967, mint
marks were not put on coins. So coins made for circulation,
that PCGS would put a MS-XX grade, might have been minted
in Denver or San Francisco.

Since the serial number on the SP SMS slab is much higher than that on the MS SMS slab I would agree with above the SP is the newer lingo. I wonder if it started around the time the 5oz ATB pucks came out as those are labeled SP as well.