Pretty similar i.m.o.
Not sure if it has been noted ( or posted before ) that in the UIHigh.sga file there is a file named coh2ui_i6c0.dds that has a portrait of a IS-1. As far as I know the IS-1 is not in the game yet and is considered a leak if evidence for it in the game files are found.
Looks like a normal IS-2 to me ..No?
I'm not on my home pc now so I can't really compare it.