89-90 Bumper :
Image
91-93 Bumper :
Image
And yes, there's a difference, the 89-90 Bumper Is verry old school looking <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/eh.gif" border="0" valign="absmiddle" alt=':eh:'> . But I guess you can replace it easly.
BTW, theres a Review on RADARS in one of the SUPERSTREET Magazines [ The one that featured the Trueno ]
It should help you decide.
TIP
Stock 91-93 Bumper Replacement : $40-$100