Good morning, Dave & Rich~
Yes - the "new" ones are made by Rich-Mar. I think the design is exactly the same as the original Herter's, though.
And Yes, the end needs to be cut down to receive the socket. I first make a shallow cut around the closet pole with a coping saw or pull saw at the upper end of where the socket will go. (I have also done it on the table saw with the blade set low and the fence set the proper distance.) I then carve the rest down with my X-acto knife. Setting it in 5200 is important to prevent rattling and to keep moisture out.
Dave - great idea with the brass rod-for-rivet!
All the best,
SJS