I definitely see where you’re coming from as it threw me off however after re checking I’m still confident it’s an alternative build. The pose is the same I think it just looks like it’s coming off something. I’m willing to bet it’s the same core of the mount with variations, I think the leg armour isn’t attached to the leg so it can be bare. The head is different and the character on top is different which can explain the cape, the alt build also looks to have a flag.
if you imagine the regent at a different angel you can see the similarities, the tail had the same ring and shape, same leg pose, same tassels coming from the seat. It’s plausible to have a different head and character. I think it’s a £35-£60 miniature. Not huge but has options like a lot of other medium-big multiparty models.
from the new year tease there is 100% an alt build shown off too