With Steve Briggs on guitar, Howard Willett (harmonica), Drew Jurecka (fiddle), and four other band members, the Bebop Cowboys’ Swing-A-Billy Orchestra brought a taste of western swing to the Townshend Theatre here last night as part of the “tour de Fort” concert series. With “House of Doc” scheduled to play in March and Aaron Lines in April, the 2008-09 season is wrapping up but passports already are for sale for 2009/010.