The blue blemish you see on the third valve slide in the third photo is only in the photo, not on the instrument. Also, a thumb throw on the first valve slide has been added since the picture was taken. The top and bottom valve caps show a gold tint in the photo, but are polished silver. However, I think they would look good in gold, and might have them plated in the future.

The serial # of the horn is 142,0XX, which would make it a 1954 LA horn. However, the bell says Fullerton, so apparently the valve body was made at the LA plant, but not incorporated into a finished horn until after the move to Fullerton in 1955. Your guess is as good as mine as to the actual date of mfg., but probably around 1956?