So tell me about the 1964 4X4 1/2 ton long beds

[60-66]

Heres some Chevy info. GMC im going to say should be close but Im leaning on less made. Ive only seen total production per year on Jolleys GMC site , no breakdown by model.
1965 K10 1/2 ton swb chassis cab 48
1965 K10 1/2 ton swb stepside 1,127
1965 K10 1/2 ton swb fleetside 633
1965 K10 1/2 ton swb Panel 103
1965 K10 1/2 ton swb Carryall (barn doors) 444
1965 K10 1/2 ton swb Carryall (gate) 433

1965 K10 1/2 ton lwb chassis cab 52
1965 K10 1/2 ton lwb stepside 513
1965 K10 1/2 ton lwb fleetside 1,459

1965 K20 3/4 ton lwb chassis cab 308
1965 K20 3/4 ton lwb stepside 889
1965 K20 3/4 ton lwb stake 1,364

1966 K10 1/2 ton swb chassis cab 40
1966 K10 1/2 ton swb stepside 1,123
1966 K10 1/2 ton swb fleetside 678
1966 K10 1/2 ton swb Panel 170
1966 K10 1/2 ton swb Carryall (barn doors) 530
1966 K10 1/2 ton swb Carryall (gate) 418

1966 K10 1/2 ton lwb chassis cab 30
1966 K10 1/2 ton lwb stepside 457
1966 K10 1/2 ton lwb fleetside 1,976

1966 K20 3/4 ton lwb chassis cab 431
1966 K20 3/4 ton lwb stepside 924
1966 K20 3/4 ton lwb stake 1,796