OK, admittedly here a 'quick read'. But... If .375 Win chambering is a contingency, why not just buy one? Mine from 1980 is a damned nice rifle! As far as "rebore", the predominant thought here seems to be such service calculated as the extent of "costs". Unless you can do it yourself, the matter of barrel removal and reinstallation as $$$. The headspace issue? The cost & complexities if having to ship an entire rifle if the case. Not sure where "cost accounting" went out the window here, but if you're a Klutz as me, you'd need the whole 'package' and 'that' making little sense compared with my above suggest purchase! Add too, based on candidate rifle description, maybe refinish or something lesser.
The net, net! Worth of such a rifle as conjured, "beauty and value", clearly in the eyes of the beholder... And not many others, seeming for sure!

Just my take!
Best!
John