That's actually one of the idea's I'm getting at.
I'm not sure all of them getting replaced is that big of an if, if you consider a factory recall, if the non-painted ones had a fault, a safety recall would have seen almost all replaced.
It culd also be a fault not relating to the paint, the paint, in particular the colour, might have been used to help destinginsh mowers that had been repaired if there was such a recall.