I have a 803 in 8x57R --- it looks the same but cannot be sure about the breach end. Mine has a bbl "wedge" device between the bbls under the handguard and the very front of the bbls can be adjusted from side to side via very small set screws that oppose each other. It is finicky at first until you find out how little it takes to move the impact.
Mine has a double trigger that I prefer.
The 803 is not as good quality as the old BRNO o/u Super Express doubles - but it is generally quite good. Mine shoots the factory targeted (using S&B) 220 gr Sierras into 1 inch groups at 100 yds. Front Trigger has a set and works very well. Overall it cost me $2000 -- not cheap but not too expensive either.
i expect the Stopper to be beefier -- but then again, the receiver of my 803 has lots of room for a bigger bore - I think mine has much too thick of a bbl at the root. Makes it a bit heavy for an 8x57R
$4500-up --- hmmmmm as much as I love my BRNOs -- that is a bit high to me, but it IS engraved by Europe's Master engraver....