I think it's ok, actually, because it isn't selling for any more than a normal battery, and will allow anyone to downgrade, even without access to another custom firmware psp. They ARE using the concept of Pandora's Battery, but they are not stealing code or any of the hard work put in to this other than the research.
My idea: A battery with 2 EEPROM's and a switch so you can change between service mode and standard mode. I bet Acidmods can easily do this. Even i could do that, but mine would look ugly and messy and wouldn't really fit very well. :P
I am 100% sure they are NOT USING THE PANDORA CODE!!
It is just the modified serial put into their EEPROM's. (which, if they are really read only, would just be PROM's I think)