Bretby boy

I have this Bretby boy playing a flute, l can find no others in this colour scheme it has Blue on trousers and hat and silver on buttons on satchel, have found others in full colour what is also really strange is the model number has been etched into the China by hand,any info would be appreciated. The others come up as 877 this one shows 877A

This early model dates from 1892.
The A usually means one of a pair, the other would be B.
Some were left unglazed (Ivorine), and some done in full colours.
This seems halfway in between the two, so maybe unfinished or a trial?

That's what l was thinking that it was a factory trial piece.

Blue is usually the first colour to be fired because it needs the higher temp; then subsequent firings for the other colours; red and then gilding being the lowest temp firings. Maybe there was a firing fault on it?

I have found these other colours on closer inspection, silver and black on satchel and waste coat has a shimmering light blue the whole piece has a heavy glaze.