You should definitely be able to do that. Piece of cake! With the right tools, it should work beautifully. Since they are “stamping blanks”, one side is bound to have a stamping burr, that they may or may not take care of. This is the “punch side”. The other side, the “die side” should have a nice smooth edge on it. Just something to be aware of. Unless they tumble them, then they may be nicely deburred on either side.
I would create a thin fixture to hold however many you feel like engraving at a time. A nice fitting fixture will keep the blanks from shifting in the X-Y orientation, and hopefully something like carpet tape will take care of any rotational tendencies they may have during machining.