Not to be disappointing, but what you know about the gun now, might be all you're going to know.
The gun, as nice as it is, and it is a nice gun, just doesn't have much of anything to attribute it to a specific maker beyond a reasonable doubt.
As you're seeing, there are several makers that might have made it, but there's nothing specific to conclude one or the other.
Sometimes things like engraving style, or even small things like the detail on a trigger guard can help identify a particular maker, but I'm not seeing anything beyond a doubt on your rifle.
But don't be disappointed! The majority of guns out there are made by 'maker unknown'. You've got a nice gun probably made around Berks Co, by a good maker, even if unknown, and sometimes that's as good as it gets. But that's not to say don't keep searching for that elusive clue!
John