Our bars don't have weights per se, they have drilled and tapped inserts in them for attaching the skinny end caps with the 3mm (I think) bolts. I installed a set of Buckhorn bars on my 03 TA and tried to remove those inserts so I could use the stock end caps. They are either crimped or welded in - they don't budge... The Buckhorn bars are hollow, so I bought a set of bar end weights from these guys..
Manic Salamander and they worked fine. I don't know that they have anything that will work with the stock bars however, you may want to contact them and see.....or maybe you could buy their weights and adapt them to our bars with longer bolts. Might be more trouble than it's worth..