If you are talking about engraving into the chrome plating itself, you will need to take into consideration the possibility of degrading the integrity of the plating and possibly lead to the plating flaking off around the engraving. This is not a concern in solid metals, only plated ones.
On the other hand, if you are talking about engraving into the wood or acrylic barrel of the pen, there are several laser engravers that are members of IAP who are capable of this, myself included.