BigBay;
There is no legislation in this country that I know of that would enforce what build standard may be applied to the term "safe". It's my belief that six business cards could be taped together and a bent pin put across one corner to secure the door, and I could sell it to you, and call it a safe. If you wished to buy it, (really good price too!) so be it.
The Underwriter's Laboratories are the best source of safe standards that now exist in the U.S. in my opinion. In order to meet their safe designation, all six sides must be quarter-inch steel plate as a minimum. Their thermal protection, fire, ratings are also the only ones to pay serious attention to. With U.L. you can go online and find the test parameters for their tests, and I think that's significant.
To my knowledge there are only three manufacturer's now offering true safes to the consumer market. They are: AMSEC, and only the very top of their line, Brown, and Graffunder. I've sold Graffunder's for years, and never had a problem being competitive in price with the other two brands. All three brands exceed the U.L. minimum build standard for a class B safe and are quality units.
However, true safes are not priced in the same category as the RSC's. You will pay more for plate steel than sheet metal. It's my considered opinion that you will also get the protection that you've paid for.
900F