That Key-op Lock is actually a very nice lock, mad in Sweden by FAS.The pick-resistance is very good.
However, if you are retrofitting a safe with a UL RSC listing, this lock does not qualify for the listing, and would void that rating. Since you were not specific about the safe, it's not clear if that is an issue.
Also, be aware that if you are facing the liberal advance of gun control legislation in your state, as we have here in the Peoples Republic of Kalfornia, that swap could get you in hot water. Liability is a big part of gun control legislation, and if you alter a product in this way and something bad happens, you could be held responsible. So, for example, if some kid broke into your safe and used your guns to do harm, that could make you subject to felony prosecution. Make these decisions with your eyes wide open....
TSG