Replacing Just Broken Camera Lens, or Whole Back Housing?

Hello, all!

Back in September, somehow the camera lens on my (then almost-brand-new) Motorola Moto G 4G (XT1045) got cracked in my pocket.

Let me clarify... It's not the lens on the actual camera, it's the glass cover that is part of the back "frame" or "midframe," or whatever the back cover you have to unscrew is called.

I would like to know if it is possible to just swap that lens? I've looked at the teardowns and guides, but they don't show this. I'd tear the thing apart to find out for myself, but my screwdriver set is on its way (two more weeks until it arrives... I live on an island) and no one that I know here has a set of precision Torx drivers.

On eBay, a bunch of people are selling the back "frame" or "midframe" (again, not sure what it's called) as a whole unit, but none are selling them specifically for "XT1045" (my specific model), and I am unsure about the inter-compatibility. There is one that is being sold as "XT1042," so I'd imagine it's the same (it's the 4G as well).

If it is not possible to just swap the lens cover thing, is it possible to swap out the middle part of the back cover (it looks to be a separate piece) with the sticker on it with my IMEI? I'd like to keep that with my phone if at all possible.

Thanks!

Nate