As a collector's item, an original 505 Gibbs would be worth...........a lot!
However, a H&W custom rifle is much better built and exhibits much better quality and workmanship and internal dynamics (steels, heat-treating, barrels, exacting tolerances) than the best of the old British magazine rifles ever did.
If you were to comission H&W to build an identical rifle today, it would cost much, much more than $29K..........