Here are pages from Oneida Community 1902 and 1908 catalogs, they both show what would appear to be a solid ring on the #4 1/2 Wolf trap drag. However, these are illustrations, drawings, not photographs. It may have just been easier to draw the ring without the twists in the ring. In fact, none of the illustrations of the 4 prong drag show a wire ring with the twist, even though the wire ring was the standard. The Oneida Community book, "How to Catch Wolves" and the 1905 "The Newhouse Trappers Guide" both show the same illustrations.
1902 Oneida Community catalog
1908 Oneida Community catalog
The 4 prong drag was made from 1895 until about 1909, almost 15 years. They were made for production, they were not that difficult to make in a factory with the proper equipment. The 4 prong drag was not hand forged, they have no hammer mark on them, they were formed with machinery. They were made from flat bar stock and the points were sheard, leaving a bur on the inside side of the prong where it was cut. The wire ring was the standard, solid cast rings may have been used at some point. The 2 prong drag was easier to make and I am sure easier to ship. The #4 1/2 was made to catch Wolves, when there were not many Wolves to trap, the #4 1/2 was used to trap Beaver. For Beaver trapping, the Y chain with a drag was in the way and most were cut off by trappers. That is why it is now difficult to find a complete trap.