That number on the cork barrel looks really fresh, and not really cleanly struck. Is there a serial number on the bell brace? That number does not look nearly long enough to be a serial number from any time period.
The slide is a bit interesting. The trumpet style water key does not look original. Also, the outer side brace is not original, as it's thinner and made of brass. When did king switch from soldered on oversleeves to the drawn-in version?
There is no serial number anywhere on the horn. And I don't know when or how the previous owner made the different modifications.