Looks like a real B18C Type-R to me. The Intake manifold, the red cover, and that hint of green by the distributor. All SiR-G's had the standard black cover.

Look at the casting code on the head, above the exhaust manifold and a little to the left. It should have "PR3" and the date cast into it.

I think that motor should have 11.1:1 compression.