The Martin Indiana is considered a step down vwrsion to what was considered Martins top horns at the time," The Tenor" and "The Alto" were the series. So, the serial number will not match up to what you see on line.

The Indiana Bank Instrument Company was gobbled up by Martin, or Visa Versa from some others perspective, at one point in time. When Martin or any other instrument making cmpany would change something for the better, the old key style they had made already in stock would become the lower version rather than top of the line.

The body/Bore is basically the same from the top line horns, so it still plays with the wonderful vintage Martin sound.

There are a lot of them out there, but they are extremely study and good istruments.

So not a rarety with a lot of value.

Myself, Id rather be playing on one of them than any of the newer student line instruments being made today. The newer horns may have up tp date keywork design, but the bottom line is the body bore metal value of the vintage American horn is going to be better than anything new in a student line.

Good Luck