I own a "first" generation T880 (with brass front F key and round F# trill key and round low C/Db keys, the later ones had a pearl front F, oval F# and oval low C/Db keys), so I'm guessing it's quite an early one, I'll send you the serial when I'm home. Another potential difference is the neck: mine does not have a strengthening bar over it... but maybe it was the same with the later T880s.
Cheers, M.