Well, I just finished the install; took about 1.5 hrs.
I didn't remove the front t-bar anchor, however I loosened the three bolts for the anchor & this seemed to make it easier to slide the t-bar out.
My biggest concern: installing the new t-bars, I used a mallet on the back t-bar anchor to drive the t-bar into the front anchor. What I noticed after the fact was that the back splines were driven all the way into the back anchor whereas the front splines had about 3/8" visible out of the anchor. I figure I have almost 3/4" of spline inserted in the front anchors so *hopefully* that's enough....
Also, when I removed the old t-bars, the metal ring didn't come out. The ring stayed sandwiched between the frame cross member and the anchor; this is how I knew when to stop hammering the back of the rear anchor -- when there was no play in the metal ring (i.e. it was completely sandwiched), there was no sense in hammering anymore.