Vintage King Instruments Cleveland 600 Trumpet Bonus Mouthpiece 314282 (1950-55)

This vintage Cleveland 600 trumpet made by King Musical Instruments was an estate find that I know nothing about. It looks complete, but I included extra pictures for inspection. It appears to have put in a closet and forgotten about for many years. The valve buttons move up and down but will stick, so im certain a good oiling is in order. Comes with an Olds #3 mouthpiece, but an additional mouthpiece (Blessing 7c) will be included. I have this listed and priced as a parts only listing due to the fact that I don't even know how to test it or work on it if I wanted to. It's likely a really good value for someone who knows more about them.  It appears to be in good condition aesthetically as there are just a couple very small dings that are hard to discern in the pictures. Serial # 314282 lines up with models made between 1950 and 1955.