There is a switch on the ram card to turn it on and off. I'm pretty sure it is a A500. Thats what it says on the bottom. Yep, trapdoor on the bottom.
It seems there might be some corrosion on the battery. However, before installing the card, during boot, it said something like: battery backed up clock not found. With the card it prints a date and time.
Not sure what you mean by socketed components. Components on the ram card?