Thanks Walt and 29chevy-
I have the Chevrolet Four Cylinder parts book dated July, 1940 as well. I also have the February, 1928 copy which is much thicker and more detailed. Something I should have looked at prior to asking the question.
In the 1928 version under Fender - Front, there is reference to the front fender Iron, left and right, and these were common between '27 and '28. This I believe to be what I would call the fender brace. There is no reference to a fastner in this area. Further down in the parts listing there is a reference to a fender left and right Ledge for the 1927 and later in the listing a reference to the fender left and right Ledge for 1928. I know that the frame horn covers are different between '27 and '28, so I believe Chevrolets nomenclature for these covers to be Ledge. As a sub-set to each groupings of Ledges there is reference to Oval Head Stove Bolt (5/16 - 18 X 1" N. P.). Could the N. P. stand for Nickle Plated?
Again looking at the 1940 Parts Book, the same scenario as noted in the 1928 version holds true, except now the fasteners are refered to as "Truss Sltd. Head Stove Bolt Less Nut (5/16 - 18 X 1 1/4 Cadmium Plate)".
I think we've answered the Front Fender Ledge attachment question somewhat but the fender brace (Iron) to fender flange attachment still remains a question in my mind. I'm having difficulty putting a 1" or 1 1/4" long stove bolt at that location. Seems as if the use of either one would extent too far into the wheel area, especially the 1 1/4 bolt.