moini.net - Jim Moini's License Plates
PASSENGER STICKERS New Jersey generally does not use any sort of validation device on its modern passenger license plates.
But there have been exceptions... like this 'experiment' from 2000 to 2005.
 
New Jersey started issuing plate stickers in November of 1999.

For better or for worse, they were modeled after the windshield stickers, with a tiny year on top, and a huge month number in the middle.
20002000 stickers exist only for
November (11) and December (12)
New Jersey License Plate Validation Registration Sticker 2000
20012001 stickers were black on purple
and somewhat difficult to read.
New Jersey License Plate Validation Registration Sticker 2001
2002In September, stickers got rounded corners,
a bolder font for the month numbers,
and the "OFFICIAL USE ONLY"
legend became more pronounced.
TYPE 1
New Jersey License Plate Validation Registration Sticker 2002
TYPE 2
New Jersey License Plate Validation Registration Sticker 2002
20032003 stickers were black on yellow
and tended to fade to white.
New Jersey License Plate Validation Registration Sticker 2003
2004Black on green.New Jersey License Plate Validation Registration Sticker 2004
2005Black on orange, same as 2000 stickers.
Last year for plate stickers.
All months exist, but months
10, 11, and 12 are rare.
New Jersey License Plate Validation Registration Sticker 2005

These stickers were discontinued in October of 2004.

Apparently the stickers did not help law enforcement tell when a plate expired.
(The year on the sticker was unreadable unless you were right next to the plate.)

And since the big month numbers actually corresponded to the years of the new milennium (01, 02, 03, etc.), I guess it got too confusing.