I am a fan of RC/VoPo Lugers (and P38's) as IMO they have a longer provenance than those that were brought back or imported after WW II. And were rebuilt to almost-new condition.
But it is somewhat unusual to find one with a 'substituted' mis-matched barrel. In general, the post-war armorers fitted new barrels to their refurbs. One would think, with their penchant for X-ing out serial numbers, they would have X-ed the mis-match number out too...
Is the bore bright & shiny, with sharp grooves & lands, no frost, no pitting, etc???