My car is registered Dec 89, and is a small bumper, and always has been.
Somewhere on the build code sticker in the boot, there will be a 3 or 4 digit code that will/should correspond to the bumpers fitted to your car, so we just need the code for big bumpers! this could get interesting 
Thom
http://igorweb.org/equidec/Default.aspx1AF = Power brake
3FB = Spoiler roof
5J1 = Rear spoiler
1C1 = Antifreeze up to -25 degree celsius tolerance up to -30 degree C
4KC = Side and rear windows in heat-insulatingglass
4GF = Windshield in heat-insulating glass
3NB = Rear seat bench/backrest, completely folding
1ME = Steering wheel
8J1 = Hand brake/low brake fluid level warninglight without inscription
8K2 = Separate daytime running lights --NAR--
8M1 = Rear window wiper and washer system with intermittent control
8BK = Twin headlight for driving on the left, with integrated high beam
8D7 = 6 speakers (passive)
3D1 = Center console
8TD = Rear fog light for driving on the left
8WD = Integrated front fog light
8F2 = Side turn signal lights
8U0 = Without additional instruments for distance measurement
1TB = Fuel tank vent line with gravity valve and PVC breather hose
1H1 = Load-sensitive proportioning valve
ADDENDUM:
Mines a 91 16v. That's all there was on the option list on my sticker. I couldn't make out the first code it was "something 2B" so that's not on the list above.
Nothing to denote big bumpers as far as I can see.