Maximum,

Based on the table in the front of the MC21 parts manual, those numbers cross reference to the NSR250R8n-III which is the 1993 Honda NSR250R SP tri-color with the HRC logo under the front turn signal.

That doesn't mean someone couldn't have sourced engine/frames from others to make it fall into that model line up, but per the parts manual that's where those numbers fall.

This was the last MC21 SP model made before the MC28 model came out in late 93 as a 94 model year bike.

I would look at it this way. If you have those engine/frame numbers, the engine is a dry clutch, you have SP suspension and magtek wheels and the body work matches the tri-color with the HRC logo under the front turn signals then it's a really good chance it's a tru 93 SP. I dont' think too many people would go through the trouble to get their ducks in a row to make that up. Maybe for a rothmans, or a repsol?
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Charles Gallant