Re:
Not read the other posts past the serial number.
But my input.
It has the powerstays of the A-Pro made aluminium-o.
It doesn't look to have the replaceable hanger (so it's the 1992 model, first two batches).
It has a stay, which adds to the first two batches.
It doesn't have riveted cable guides, so that makes it the second batch.
That batch is A106 (1991 June).
Yours is A910(1)
Which could possibly be a 1989 Nov model for the 1990 years
Or a different coding and 1991 Jan, it could be as it has 8 numbers and not seven.
(Cheshire1980, did the Feb 1991 batch use this coding and not the newer style?)
Either way, it is earlier than the Aluminium-o.
I'll leave it there.
Caveat - at least last time I looked it's been some years now.