Boehler steel is Austrian from Kapfenberg, Styria(
http://en.wikipedia.org/wiki/Kapfenberg ) . I wouldn't mix the terms German and Boehler unless it's a German gun with Austrian tubes or an Austrian/Bohemian gun with German tubes. Both countries were dependent on finite sources for components and companies like Sauer and Simson are German examples with Krupp steel tubes almost exclusively coming from Sauer but I'm not sure of who made the tubes of Boehler steel. I. Meffert used Ehrhardt lauf tubes(
http://www.fundinguniverse.com/company-histories/Rheinmetall-Berlin-AG-Company-History.html ) and I'm sure there are other examples. I'm also sure that a few companies had the monoploy. Brothers Boehler began peddling other's steel products in the late 1800s and info can be found here:
http://www.bohlersteel.com/ . Many Bohemian guns have Boehler steel (select "Brand" from the lefthand tab and then "Tradition").
Ken is correct on the V.T. because in 1930 the Brescia proofhouse was temporarly moved to Gardone Val Trompia with the proofhouse at the Beretta facility. The "star" may be an indication of choke. Pics would help tell the tale.
Kind Regards,
Raimey
rse