per the title, just interested in knowing if there are any markings or other ways to identify if the fender on a 91 Trans Am is GM or aftermarket. I see some characters on the top of the fender edge that's covered when the hood is closed but not sure what these markings mean

 

If it's the original one from the line. It will have a sticker with the VIN number on it somewhere. If it's been replaced look between the wheelwell and the door piller "Sometimes" you will find a part number tag...

 

Should be a sticker with the vin on the backside of fender if it's original

 

GM stopped putting VIN decals on all the panels before the 1991 model year.

The edge of the fender just above the bolts that retain it to the frame rail will have a few stamps. Generally, a 91 will have "90" as part of those stamps as a date code.

Aftermarket fenders often will have a label on the backside, even GM replacements. It's not too unusual for people to leave the label stuck to them.

Beyond that, I can usually tell cheap aftermarket replacements by feel. They seem lighter, and more tin-y, more flexible. Idk, it's hard to quantify, but it's a difference you can feel.

 

thanks. Yep, thought the vin decals stopped by 90. I see a few stamps as mentioned; pretty sure it has '90' in the sequence.

My reason for querying is that the fit by the door isn't the best; seems tighter by the bottom but toward the top the gap between the fender and door is a bit wider. Lots of possibilities but seems here the fenders may not be the cause

cheers

 

Start at the mounting tab at the bottom of the fender. The pinch weld doubling as a jacking point often results in the pinch weld and the fender mount getting mangled and throwing off the alignment of the fenders. They're easy to bend.

Door hinge sag and body sag are other possibilities that come to mind.

 

yep tabs look straight and hinges have recently been done. Suspect body twist as door looks original aswell (tags match vin).

God bless thirdgens...