You are right. we may want to call it a Harihara - but cannot as the depiction of the weapons as well as the form of the idol in general does not conform with the norms of the Harihara.
on a side note the weapon in the lower arm also potentially looks like a Vajra - in that sense we might have to explore the pantheon of the Buddhist iconography of far east...!!! but this is just a speculation and I've no knowledge of the icons in Buddhist religion.
My guess is this is a mix created by some innovative mind
Thanks,
Bhushan