As far as I can tell, these counterfeit operations (as opposed to "legitimate" unlicensed developers making an original product) have a generic template to produce GBA boxes. The GBA logo on the front left is always the same quality and they usually have the same UPC code and warning paragraph. I've gotten a bunch of commercial games that you could tell the cover art was blown up from a shitty low dpi scan grabbed off the internet, but the logo on the left was still high quality. The backs are sometimes the same as retail or just a simple colored background with some screenshots and cut & paste text grabbed somewhere from the net.
Besides PocketNES hacks and fan-made Pokemon stuff, the only unlicensed games I've run across put out by pirates has been Digimon Ruby and Sapphire. I guess the protection routines on unlicensed GBA games worked out since they weren't cracked until long after pirates moved on from GBA production.