For the differences between Ames' and Collins' standard bayonets go to Ames vs Collins.
The edges of the Collins' cross guards are squared and the space between the edges are flat. This creates a very well defined finial. This feature is common to all of Collins' production.
The steel rivet in the center of the cross guard passes through the blade tang. It is a feature found on most of Collins' bayonets but not all.
The Collins' press stud spring is normally 51 millimeters in length. This length is longer than most springs produced by other manufacturers. The width of the spring is approximately 6.5 millimeters. Collins' spring appears to have been stamped out of thin sheet metal leaving the spring the same thickness from end to end. Thus eliminating the tooling that Ames and Harpers Ferry springs require.