Interesting. Yes, when I bought my C1 there were two models I looked at with a $100 price difference. They were identical other than the more expensive one including a HEPA filter where the cheaper one had the Air Clean filter and holder. But a HEPA filter by itself only cost $55, so I bought the cheap one and a separate HEPA filter.

In case it helps, here are the bag+filter packages I've been getting:

https://smile.amazon.com/dp/B00UTFZAII/

This definitely has both the throwaway Air Clean filter and the scratchy pre-motor filter.