Originally Posted by atomicfungus
I always thought they were just sample models made in very limited (5-10) numbers to look for printing errors.
They are separate runs done and different from sample models as I also have several sample models by Jet-X, Blue Box, Magic and Sky400. All these models have printed on their underbellies the word 'Sample' with standard prototype colors.
Unfortunately often on e-bay, various sellers will state that Golden or Gold plated models are samples. They're not though! They're a separate run of 10-20 models, usually completed after the original prototype run of models.