As cast Go.....and I don't remember what they measure...lol. I think there's some on the shelf and I'll measure them. I think the groove was .446 on both barrels with the right barrel showing a bit larger, like .4465 or maybe .447, which isn't uncommon in an old double that's been used. I bought that rifle in the early 90's which was when I did the work so, details might be a bit foggy.
I have a Vierordt double in 8 X 65R Brenneke and a Merkel O/U in 8 X 60. Both their bores measure the same but, the Merkel is between the wars and the Vierordt carries proofs from just before WWI. The Vierordt is Czech.