Just thought about posting an update on my new t-bars from Sway-A-Way via AC.
On May 17 (Fri), I received a replacement t-bar from AC.
According to Sales Rep. of Sway-A-Way, three engineers examined the passenger side t-bar that I returned. They all said that there was nothing wrong with it, and they were going to return me the exactly the same t-bar. Of course, Mike (AC) thought that it wasn't going to work, so he sent me a new passenger side t-bar from his own stock. The next day (5/18), I attempted to installed the one from Mike's stock. There was absolutely no problem installing it!!!
That simply concludes that Sway-A-Way engineers only (possibly) checked the diameter of the t-bar itself, but not each splines. It must have been one of the splines that was slightly too large, so that I could not make it fit at all.
...So, Mike is receiving the DEFECTIVE t-bar from Sway-A-Way because Sway-A-Way does not admit (or failed to find out) that it was, in fact, DEFECTIVE.
I am glad that Mike did what he did for me (I am happy about the t-bar purchase from AC), and I really appreciate his help on this.
I hope everyone else who is purchasing Sway-A-Way t-bars to upgrade realize that you might have to face the same problem... (I'm sure the possibility of that would be very small since they've never heard of this problem before...) Good Luck!