I stumbled across this advertisement recently in The Mexican Mining Journal, vol. 6 (April 1908), p. 31. The distinctive clip immediately identifies the pen as a Diamond Point, as one can see from the ad below which ran in American Exporter, vol. 61 (Jun 1908), p. 140.
The Hispano-American Export Company even kept the same model numbers, but they added a generous markup: $2 for a basic No. 50 eyedropper, including registered mail "to any post office in the world", for a model that could be bought from the manufacturer for $7.50 per dozen (I haven't been able to determine exactly how much the shipping would have been, but at the time registration cost only ten cents, and a domestic letter only two).
Diamond Point does seem to have been pushing export sales. Looking back through old copies of American Exporter, there aren't many fountain pen companies paying for ads, and most advertised for a just a year or two. Diamond Point wasn't advertising in 1907, but made a tentative start in 1908 (Modern/A. A. Waterman, Smith, and Wirt were the other penmakers advertising that year, all taking out much more ad space). In 1909 Diamond Point became a regular advertiser, joining A. A. Waterman and Crocker.