Hardware replacement needed
The 32-119 likely can replace these old drawer sockets; just make sure that size of the gap that accepts the track matches up. These newer style sockets mount to the back of the cabinet with screws.
Now, getting the bases for the old sockets off can be tricky. It's possible they may be partly glued to the back of the cabinet. In that case, using a nail polish along with a putty knife to gently pry them loose may be your best bet.
Also, someone told me the piece that is attached to the cabinet, in the back, that I am unable to remove, may be a spreading type bracket. He said once it goes into the hole, it widens and then is very difficult to remove. Have you any experience with this type of system? Any suggestions for removal of the old bracket?
Maybe I can help! Your existing bracket is a "push in" that attaches it to the back of the cabinet. You should be able to pry it out in the back of the cabinet using a flat blade screw driver or a flat chisel like the 75-026 or a small pry bar like the 75-081. The 32-119 bracket is a one piece type that screws onto the back of the cabinet.