How rare is a GA4 paint code demon?

The Y codes on the fender tag will identify if it was a car ordered by the dealer as floor stock, or whether it was ordered by a customer.

Actually, no.

Not all tags have Y codes showing ordered or not.

Y14 would indicate that a deposit was put down at time of order. This deposit could have been made by a customer at a dealership or the dealership ordering its own stock. (Y14 should not be confused with Special Order which is Y39)

Y16 indicates an order initiated by Chrysler to be shipped out to a dealership later to be determined in the hope it would sell.

Some car invoices show Y14 & Y16, in these cases the dealership maintained a balance with Chrysler to offset the prices of the cars sent to them for lot stock.