I cannot speak for the FN-made clips for their version of the Browning Semi-automatic rifle. However, the clips for the Remington Models 8 and 81, which were the American versions of the same rifle, took clips made by Remington (or perhaps subcontracted out, I don’t really know which) that were unique to these rifles. There were three types of clips, each available in two forms - one for .25, .30 and .32 Remington caliber rifles, and one that worked with either .300 Savage or .35 Remington caliber ammunition. Those are the five calibers the Remington rifles were made in. Two of the forms are brass, while the third is a very flat steel stripper clip. They cannot be mistaken for other clips, since all are caliber marked on the bottom. Early catalogs indicated that each rifle came with three clips. In 1906, these clips were ten cents each. Instruction manuals from the early years of the rifles showed the clips as part number G298, with no differentiation for calibers. You specified that with your order, at a price of 20 cents each. By 1951, the clips were 95 cents each, and were differentiated by part number for the two caliber types - Part number 490 for the clips for .300 Savage and .35 Remington, and part number 495 for those that held the .25, .30 and .32 Remington cartridges.
One of the production types was brass with three bumps on the side, the center bump being lower on the clip’s side than the other two - they were not in a straight line like a 98 Mauser stripper. The second type had one single bump and is similar in appearance to that in the FN drawing, although not identical. It, too, was brass. The final style was steel and very flat, with a single bump on the sides. In each case the clips for .25, .30 and .32 had a shorter bump than did those for the .300 Svage/.35 Remington.
The two brass types were grooved on the bottom, with the two outer grooves running the full length of the charger, while the center groove stopped on each end well short of the edge of the charger. The caliber was stamped at one end of the center groove. The bottom of the last charger was flat and had only two square cut-outs for attachment of the spring.
Hope this is of some interest. All information is from the book “The 8 and the 81, A History of Remington’s Pioneer Autoloading Rifles,” by John Henwood, Revised second edition, pages 111-115.