The original denomination for the round is 7.92x57 I and 7.92x57 IS.
In reality the two cartridges are different, the old "I" (or sometimes named "J") was .318" in bullet diameter and was loaded at lower pressure, the newer 7.92x57 IS (or JS) where "S" stands for "Spitzer" is a higher pressure round with a bullet diameter of 0.323.
The name "8 mm Mauser" is an American synonym for the cartridge loaded with 170 gr. 0.323' bullets. Because of the potential use of the cartridge in older (.318" caliber) and weaker "I" bores, the "American" 8 mm Mauser is loaded for safety reasons at very low pressures, somewhat even lower than the old spec 7.92x57 I cartridge.
As far as I know, commercially only RWS and Norma load the 7.92x57 at full "IS" specs.
The K98 should be perfectly safe to use with the higher pressure round. As a matter of fact, the K98 can handle the even more powerful Luftwaffe (German Air Force) rounds, the so called "machineguns ammunition", without any issues.
In a few words, while the full spec 7.92x57 IS is equal and in some loadings even a tad more powerful than the 30-06, the commercially available "American" 8 mm Mauser is not....is closer to a 30-30 than an '06.