This is a 1948 (first year) Los Angeles Olds Studio Bb trumpet. The Studio replaced the Standard or "Olds" trumpet in the lineup in 1948 at the same time the Ambassador was introduced and the Recording model replaced the Super Recording.
These original Studio model trumpets featured a nickel-silver bell flare and a nickel silver tuning slide crook, which provide for "brilliant response" as described in the Olds literature of the day. This particular instrument is one of the lowest serial numbers we've ever seen for a Studio and is lower than any recorded on the Olds Register, so this one of the first produced. It still has much of the original lacquer and the valve compression was excellent, so likely this horn has been stored for much of its life. This trumpet clean inside and out.
All slides are smooth. Engraving is sharp and clear. Matching serial numbers on the valve spring barrels. Does not come with a case.