If they did a good job of adding it, I would keep one on if it was me. If they rigged it up, I would do it in a correct way.

I knew I had a picture of the factory filter somewhere. Ignore the wonderful wiring hack job.

 

Yeah seems to look fine to me just an inline filter i suppose. When I go to change it out I guess I can find a suitable replacement. Yep that filter is identical to mine.