fairly impossible really, the physical thing is just an EPROM chip, it's the software loaded onto it that you'd need to look at. Buying an EPROM reader to do that is insane given the value of a chip like this and even then the hex code you get off it probably isn't going to mean a right lot to you. You could send it off to someone like PPP and they may be able to tell you what map is on it (it could just be a home made one though) but I can't see why they would do this for free and given it's value is probably £20 at best, seems a waste of time. I'd just throw it in the bin.