1970 Matchbox Series No 59 Ford Galaxie Fire Chief - Production error?

1970 Matchbox Series No 59 Ford Galaxie Fire Chief - 
The Ford Galaxie was produced from 1966-1970 and had two versions
This is the 1970 Fire Chief final version. In very good physical condition with intact blue light and tow hook. Paintwork is has some light play wear. But what makes this one stand out is the second decal on the drivers side, most likely the result of a production error.