Lang is a BV2 maker's name. The gun is most likely a "best work," "A" grade, or "B" grade Original Quality. The Current Condition should be around CC6 = Shootable but needs some repairs and refinishing or refinished with barrels or stock replaced.

BV2-OQ1-CC6 = $6,655, BV2-OQ2-CC6 = $4,652, and BV2-OQ3-CC6 = $3,480. Good photos will help narrow down what this one really is. BTW, BV2-OQ1-CC1 (pristine) = $30,000 and BV2-OQ3-CC9 (wall hanger level) = $718.

Hope this helps a bit.

DDA