'L' does equal Luxus which is a standard action with a walnut stock <img src="http://jsramsbottom.co.uk/bbs/e/icon_biggrin.gif" alt="Big Grin" width="15" height="15"><!--graemlin:--> whereas the Export had a walnut stock with a longer 22 inch barrel.
Yours should also have a leather piston seal if it hasn't been retro fitted with a nylon one.
I'm surprised BSF NUT hasn't joined in this discussion with his knowledge on the subject.