The fenders on the ZR2 are different than a regular Blazer , as stated there is a lip on the ZR2 fenders for them to bolt up to ...
As for the price of ZR2 flares , I just cracked the small front/right lower flare or flarette going through some snow and it hit a chunk of ice , the price fore this small plastic flare ( 9" long ) from GM $279.00 but he would give it to me for $249 [:@]
I asked how much the whole flare would be and it's over $700 for one flare !!
I found one on the net for $70

Zed

 

Yeah ZR2 Fender Flares are expensive, EGR makes some for the 4 Door which probably what the member above saw on the 4dr zr2 stickered blazer. If you want those EGR Brand ones CLICK HERE

Otherwise here is another thread from a little while ago with some more info https://blazerforum.com/m_67694/tm.htm

Hope this helps.

 

Does the flange bolt on or is the sheetmetal itself different? Doesn't make a whole lot of sense to tool up completely different fenders and quarter panels...