Ok then...Well....I think there is no other "formal" indication about your chassis type except the blue plate i've told you before, which is however not a guaranty.
EK9 chassis is a complete racing package. Check for: recaro seats, racing steering wheel(and response), red floor color, racing supspension(stiff), rear ABS, are some thinks to have in mind. To check for EK4 is more difficult since the interior does not differ at all from the cheapest civic around. However you can check for rear ABS, and good suspension grip. For other types don't feel so anxious.
Both EK4 and EK9 have that cross bar above the engine for better allocation of the forces exerted at each side of the car when cornering
. I hope I have helped you a bit.