You would need to find a board which uses a chip with the same pinout as the replacement, otherwise you may be plugging the USB cable from your computer in to pins where it's expecting to find the keyswitches - best case it just won't work, worst case you connect 5v to the wrong pin and fry the chip.
Physically desoldering the chip is certainly possible if you have the right tools, I only lifted a couple of pads when I removed the controller chip from my Ducky using a mini blowtorch but I didn't attempt to replace the chip directly for the reason above. Instead I connected the existing matrix up to a Teensy to make it programmable.