Alot of replies here now, great! These are still murky waters for a DR-rookie such as myself.
I have a Blaser R93 6.5x55 with a leupold and a Lamber shotgun, so this is quite a step up on everything and as such I want as much info I can get!

The current owner said "all shots within 3 inches" at 100 meters, but in 5 years of ownership he has fired 30-40 shots total, whereas the weapons dealer who sold him this weapon has been in business for 40 years knows this rifle well as the owner and has been kept up to date on this weapon, stated 40 mm at 100 meters ( and he has no financial interest in this weapon anymore, he is just a nice guy. I spoke with him on an hour on the phone even if he knew I wouldnt buy anything, genuinely nice guy and double rifle enthusiast) so it might be the current owner who are confusing stats.

As for the regulation, I have sent him a mail now asking if the rifle is regulated with the new leupold aimsight, with open sights or with both.

If its only regulated with the Leupold sight, that is fine with me tbh. its a 1.25-4.20, so as such I can find most game inside the scope :P