A true Si hatchback will have the engine : D16z6. To find that out, pop your hood. Then look at your engine. By the exhaust manifold on the right side you are going to see a few numbers.... what does that say?
See the exhaust holes with paper inside them? The far left you will see a flat spot and it has the engine code there. Another way to know if you have an Si or not is: Does you hatch have a moon roof?(I think all Si's came with them) Does your car have power steering ? Does it have air conditioning? This will tell you if you have an Si or not. Also, Do you have a rear window wiper blade?
I hope that helps.
Oh yeah.. this motor you are looking at is a Si motor from the hatchback model you have.