The reason for the lettering showing up on the early kits is that the kits were a "next step" marketing decision for former promo assembled model cars that dealers passed out to buyers; the business, like AMT, just packaged the unassembled plastic parts into boxes with cool looking box art, sent them off to the hobby shops and such, and we youngsters were hooked into doing the assembly work ourselves. And we "oldsters" are still "hooked"! ?
Joe