With claw-mounts this is simple enough to do with the aid of a gun-vise or makeshift clamp, so the gun doesn't move while attaching the scope after aligning the iron sights.

With the relatively light-weight high-velocity small-bores like your 7mm, there may be some change in the regulation after fitting the scope. The big-bores are by all accounts much more forgiving, though my experience with scoped doubles is extremely limited.

Be sure to keep us posted.