The 458 is the 458 WinMag. This case is 2.500" long and uses a standard magnum bolt face and shoulder dimensions. A 375 also has the same bolt face and belt dimensions but is about 2.850" long (someone else here will know the exact length.). If you expand the neck on a 375 case so that the case is straight ,it will be a 458 Lott. You can buy 375 basic brass ,which is not necked down and this can also be used in a Lott if it trimmed a bit.(this is what I use). So a Lott is a lengthened .458 or a necked up 375. In a pinch you can use 458 brass in a Lott ,but Lott brass wont fit in a 458WinMag chmaber.
PS ,some Lott chambers are only 2.800" long while some are 2.850+ long