I think the hardchrome rumor on huglu guns is most likely BS.You cant engrave hardchrome, nor can you retain detail by engraving and then chroming. I think that they have a chrome rich finish that they are calling "hard chrome," but it should not be confused with the common process of HARDCHROMEing which is and entirely different and more expensive process.
I may be wrong but thats my belief.
Also, you can NOT color case harden hardchrome(if that is in fact what it is), and you are likely to ruin the gun if you try. You will most likely end up with peeling/flaking chrome if you attemp this.