Another noticeable difference I can see between my 87 XLT and my 94 XLT is the black body side molding on the front fenders is different.
On my 94, the molding seems to be shorter, while on the 87, the molding seems to be closer or extends more to the wheel well opening.
Oh, and there is some sort of difference on the 87 vs the 94 from the distance directly under the front headlamp assembly to the top of the front bumper and from where the wheel well arch meets that area.
Those are my observations. The actual contour of the 87 & 94 fender "lips" appears to be identical - of course by the human eye, but I have not taken any physical mearsurements to compare scientifically or for true tech specs....