62-1847 = 1962 impala 2 door hardtop with V-8 motor ( above these number will be a number and letter that tells what month and week the car was built at St Louis GM plant
SL 12950 = St. Louis fisher body plant 12950 fisher body #
trim 843 = Medium blue bucket seat interior - confirms that car is a factory SS car
Paint ?
EZI = tinted windows
12H = St Louis GM plant numbers for factory SS car
your VIN serial number on door jamb should confirm matching tags if its a St Louis GM car and the body type in the numbers
Paul