Thats what my research so far is showing also. I'm looking at Classy Retrofits which was linked from the forum. 20 years ago I'd have done it myself, but arthritis and fibromyalgia have decreased my hand strength and dexterity to the point that it's worth it to me to spring for a pro job.
Nice ride by-the-way! I've owned and/or driven several Buicks over nearly 50 years and have a lot of fond memories. Favorite was a '62 Le Sabre that belonged to my best friend in high school. We took it on a cross country trip after graduation in '69, before we went to Navy boot camp together. Montana didn't have a daytime speed limit back then and that big 425 (if memory serves) V8 would just purr along at 90+. He later knocked off the exhaust crossover in a parking lot, then it was more like twin .50 caliber M-2 Brownings underfoot!