The barrel looks newer than the rest of the Luger. Also, IIRC, one of our members here makes replacement barrels for Lugers because of some arcane barrel length requirement by the Canadian authorities. It might be worth measuring the muzzle-to-breech length, not that it matters here but it may have been swapped out in Canada.
Nice looking Luger. My WAG would be in the $1200 to $1500 range, depending on the abundance or scarcity of Lugers in where ever you live.