Actually the first Nine Production Models were the only ones with constant dyhedrial and classified as B-25. The 10th Production model birthed the B-25A
Gary, I don't know where do you have this information from, but it's incorrect.
The first 24
B-25 (no letter) were the NAA No. NA-62, contract# W535-ac-13258. As you mentioned only the first 9 of them had initially constant dihedral. But the 10-th a/c manufactured was still a B-25. The s/n for model B-25 are from 40-2165 to 40-2188.
B-25A, NAA No. NA-62A were manufactured upon contract# W535-ac-16070 for 40
a/c with s/n from 40-2189 to 40-2228.
By the way the survivor "Miss Hap", s/n 40-2168, was the first B-25 delivered to the first BG. to make use of the "Mitchells" - the 17-th BG. It was a HC a/c. Later on it was returned to NAA damaged, before being "upgraded" with flat outer wing panels and later modified for gen. Arnold. There are some amazing memoirs by Lt. Boardman C.Reed from the 34-th BS., 17-th BG. about the deliveries of the new B-25 to McChord field in 1941. He even flew his first B-25А, s/n 40-2202 later coded 47-17В from Inglewood. Sadly, he passed away on March 12, this year. He was 99!
The Inspector wrote:
....Dirty Gertie is another case of the msn falling in a hole in Baughers lists her closest production line mates went to the Med theater so I'd guess it's just touch ups from newer paint supplies over sun bleached dings and scrapes.
You are right not only because of the s/n, but also because of the desert camo. No a/c from the 3-rd AG could have such camo. "Dirty Gertie from Bizerte" was apparently a 340-th BG. bird (this information is from one source only - a book with XL-sized posters of WWII a/c). It might be a plane from another group, which went to the 340-th later - I don't know exactly. The name is the title of a GI song from North Africa. Bizerte (or Bizerta) is a city in Tunisia and Gertie was a...
"queen of the night" from there. This particular a/c was painted sand (shade 49) over neutral gray (shade 43). "Sand" is commonly known as "desert pink" (or "titty pink"), but both names are not official color or paint designation. At some point NAA stopped the production of sand-camouflaged "Mitchells" and the depots in North Africa obviously didn't receive any paint of the same color to refresh the repaired a/cs. All repairs were done in OD. It's visible that the de-icing boots were removed too and the blank metal was painted OD.
Another a/c with similar patched camo (not so heavy!) is this one:
A B-25C-10 from the 340-th with the wrong interpretation of the new insignia with white bars on both wings. This a/c shows the initial operation "Torch" insignia with the yellow border on the right, later overpainted. The de-icing boots are just removed, but the bare metal is not overpainted in this case. The s/n is not the original one (in yellow), but added in black in the field.