I'm honestly not suprised by this at all. For all there is a vocal group that hates everything to do with the Clans. I think most people like them well enough, and much like the HBS PC game? We're at peak nostalgia for people who grew up with Battletech, so people have money to spare and definitely want in on stuff like this!
I wouldn't be shocked if this hit well over a million, or even 2 million by the end. Maybe a tad surprised at the latter, but not shocked at all. Especially as new stretch goals add new add-ons for people to throw even more money at. I mean, I can already say I'll add on a star of elementals at the bare minimum.