The specific lock's design is just as important as the rating, IMO. A UL rating does not necessarily speak to the quality, reliability, or longevity of a design. Someone purchasing a safe or a new lock will want to inquire as to which specific model lock they are getting.
For example, the S&G 6741 and the S&G 6730 are both UL-rated Group 2 locks made by the same company, but they are as different as can be. The 6741 is pretty close to junk. Using less expensive materials than brass, these locks are not known for reliability. On the contrary, the S&G 6730 is the benchmark of a quality mechanical Group 2 lock and is the benchmark in which mechanical combination locks are compared to (and based upon.) Buyers should look past the marketing and demand to know the specifics.
But with gun safes, how much do lock specifics really matter? Regardless of what lock is used, the standard design model that most gun safes are built to are not designed to resist a physical attack. Most of these attacks will target the sides or top, where criminals are well aware that the armor is often thin enough to be defeated in seconds...?