Drifter420 was right - the easiest way to tell is by looking at the instrument cluster. Non-supercharged models have a voltmeter, and the supercharged models replace the voltmeter with a boost gauge. The SSE model can come with almost every option that comes on the SSEi so sometimes it can be tough to tell them apart.
As for the dark blue metallic color on the SSE/SSEi... you are right, they are rare! I have only seen two in all my travels and looking at used car ads for over 6 months. I have a 92 SSEi with those nasty blue wheels (soon to be replaced), and beige interior. There is one just like mine at a local wrecking yard - blue wheels and all - but it has gray interior so it'* not very useful when it comes to parts. Other than these two, I've never seen another one. Seems the more popular colors on the SSE/SSEi models are black, white, red, and green... very few of us blue ones out there. I'd be interested to see how many of what color left the factory in 92 just to see how rare this color is.
From what I have researched on 92-99 models, the dark blue metallic (code 29U) was only offered in 92 and 93, and the body-colored alloy wheels were only available on the 92 model. In 93 you could get the same wheel design, but only in silver.
You should have no problems showing that SHO who'* the boss!