welcome to the community!
looking forward to seeing photos of your rifle. you’ll need to shrink them down quite a bit to post to the forum, or post on imgur or = then post a link. it works best if the rifle isn’t oily & outdoors on an overcast day (not direct sunlight)
Circumstances among the two arms factories weren’t quite as you describe. Corporate ownership may have been the same before 1938-39, but Brno is in Czechia & Povazska Bystrica is 190km distant in Slovakia, a 3 hour trip today, longer in the ‘40s. These were separate countries at the time. People did not commute daily like that then as some do today. so connected, yes, making the same product under occupation yes, but dot & dou rifles aren’t exactly the same as you can see from the examples show in the Photo Reference here. dot didn’t make dou marked rifles & vice versa, though either may have reworked salvaged receivers with other factories’ markings. Brno was liberated on April 26, ‘45, much of Slovakia a month sooner, but in stages, as the soviets wanted to ‘pacify’ any areas involved in the Slovak rebellion against the Germans. (similar to what they did in Poland)
my apologies to
@AndyB if I’ve mispelled or misdescribed any of the above.