Try ebay, amazon or rock Auto...
There is some on e-bay, here is what I found.. http://www.ebay.com/itm/8M-Big-D-Shape-Car-Door-Window-Trim-Edge-Moulding-Rubber-Weatherstrip-Seal-Strip-/332135091357?fits=Year%3A1997%7CMake%3ABuick%7CModel%3ALeSabre&hash=item4d54cb4c9d:g:0LwAAOSwdGFYrUvi&vxp=mtr
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