I did a few mins of research for you trying to work out what the difference in models is. I can only find 168 or dc60 or unspecified models, I'm not quite sure what the difference is. Here's a page with a bit of info.

I'm not sure who makes the original firmware so you should look around yourself. You want to make sure it offers the best 640x480 recording and doesn't upscale from a lower resolution.

Reading through the reviews that one you linked doesn't look very reliable. So I'd look elsewhere and read other reviews, try and ignore some of the ones that complain about fuzzy picture, focus on seeing if the product is legit and works correctly.

You will also need 3 of these.