any shots of the other side?
usually theres a revision printed some where on a pcb, its not just a Nintendo or video game thing, pcb's in generally have a revision silkscreened on them if they are made from decent manufacturers.

any way I don't see any sort of revision on those pics and I have a feeling that along with that revision you might find that region it was meant for.

problem is its hard to tell from the component on the board because I am pretty sure the region lock out on 3ds's is a sortware thing, programmed into the firmware, that's more common these days.
its not often you find hardware region lock out in a modern console or handheld they left it all up to software and that way to, some companies left it up to publishers to make it region specific.

Nintendo is pretty good about silkscreen part of the region code on the pcb's so it should be on there someplace