I know Donnie Brown is interested in this as well as others. My '26 roadster is an October 25 edition. I recently purchased some rear fenders from eBay which I assume are of the later variety, and here are the comparisons.
The ebay one is black and the left fender and my early 25/26 is gray and the right one.
Bolt holes to the running board. Early: round holes. Late: square.
Bolt bolt holes to the splash apron. Early: two. Late:three.
Reinforcement brace: Early: none, Late: present.
This is what I am not sure of. In the late fender, there is a reinforcement plate behind the license plate bracket. My original right rear fender had no indication that there was one but that area was pretty badly mangled.
Ok this may be some bad news and someone correct me if I'm wrong but the rear fenders for a 26 are different depending what they came off of. Touring rear fenders are different from Coup. That's why they don't make repros for the rear except fiberglass.
I think the difference in your fenders, is repo and orginal , they did make repos for coupes and roadsters years ago.
The factory 26-27 roadster pick up did not have a tail light on the fender, it hung below the box and the fender was not drilled and did not have the reinforcement plate. The 26-26 coupe, roadster and roadster pick up all shared the same rear fenders but the coupe and roadsters had the tail light on the fender.
There are a few differences Im aware of to the touring/roadster rear fenders. Tim is correct that the roadster pickup did not mount the tail light on the fenders, so no holes or plates were needed for roadster pickup fenders. The 1926 non starter cars do have the holes for the tail light but they were not used. The oil tail light mounted to a special bracket mounted to the rear spring clamp bolts. Ford did not even try to hide the holes on the fender on the non starter 26 models. The non starter option was not offered in 1927. So all 1927 Improved models will use the tail light mounting holes and plates for the electric tail light. As to the round vs square holes. I have not seen enough examples to form a good conclusion on them yet. One other problem that we run into is the "replacement" parts or "spurious counterfeit" parts that were available during the T era and even into the 30s 40s era, and later. These were supplied by Western Auto, Sears, Montgomery Wards and hundreds of other suppliers. If the parts were changed, for example, during the 30s 40s era. It would look just like an original parts as to age and wear. The two holes vs three holes and reinforcement brace vs no reinforcement brace is typical of some of the early problems of the Improved Models that Ford was trying to fix in the August to December 1925 time frame. I am starting to lean toward the holes and brace/no brace is one of those variations. But the jury is still out on it at this time. Will, thanks for bringing it up for discussion. Its discussions like this that bring more info to light on the changes to the Improved Models. have fun and be safe Donnie Brown ....
Here is something more to add to the mix. My other fender (left side) which I assume is original to the Oct 25 build (shown here below in gray) has the reinforcement plate. The theory is that Ford was switching over to fenders with the plate but was using up the old fenders as was the case with my right rear fender.
Also shown is a photo of the reinforcement plate for the taillight of a Canadian '26 (I believe) which the owner said the car was 100% original.
And, where does the wire from the taillight go into the car body? My car seems to not have any hole to accommodate the wire although I do see one in the Canadian car. Is that correct, or was that also a variant?And if so, what diameter is that hole?