So something is not adding up here. It 'appears' the bands match. The front band almost looks like a 53 and the rear kind of shows 3 then nothing not sure but then why the stock is capture replacement?? Almost always in a sport job the bands and bayo lug are gone too. Maybe the stock was badly damaged some other way? Huge damage to the wood? Water damage or delamination? As pointed out the bayo looks dynamite. Nice finish and unsharpened. You say it's matching? Are there stamps on the frog? It also looks to be in great shape. Another point that would help besides more info on the bayo and frog is if all the parts are truly Gustloff everything will have an additional mark. As the trigger guard has a d you should find i, a, e and l among others. On every part. Is the bayo lug numbered or so marked?