A verifiable answer popped up here in less time than it might have taken to generate an email that may never have been answered. Now I know.
Yeah, verifiable how, and when? The poster just below you who obviously has no small amount of knowledge about Italian doublegun manufacturing methods doesn't seem to be as convinced of their being of chopper lump construction as do you. While you now sit back convinced you have the correct answer you could have placed one phone call to the company and gotten an answer straight from the horse's mouth. While you THINK you know the answer from replies on here I reached out by phone to Upland Gun Company and spoke to their representative in an instant. He answered my question about barrel joining and the answer was NOT what you thought you "knew".
UGC said they use both mono-bloc and demi-bloc construction. Mono-bloc is the default method used on the lower priced model S X S ((Zeus) with demi-bloc being used on the upgraded model (Venus). However, and you could not have found this out with anything less than a phone call to them, they WILL build the Zeus with demi-bloc barrels upon request, roughly a $400 upgrade option.
So, CZ, while you rest in your answer you THINK is correct, based on hearsay, there is the REAL answer. You should team up with ed good. Both of you would rather generate a post designed to have someone else do your legwork for you than do it yourself. That phone call took me all of three minutes, and cost nothing. I could care less that YOU get a correct answer to your question. I made the call because I wanted to know, for my future wants. BTW, the rep I spoke with thanked me for calling and asked me to call again, so he didn't consider it a waste of his time at all.