No. The GBA has a piece of plastic covering the glass LCD screen. The screen that you're touching on the DS touchscreen is actually the digitizer, which sits above the LCD and basically translates screen contact into coordinates. They're replaceable in some PDAs, but if it becomes scratched you generally just have to deal with it, although a few people have used cleaners to buff out scratches. Best thing to do is use a good screen protector and just be very nice to your touchscreen.
