I smoked plenty of Thai stick in the 70's. The real stuff came on a 7 inch stick,wrapped in a hemp fiber,and normally pressed into a bundle for transport. It wasn't treated with anything,however it was the first mature seedless crystallized weed most people in the States ever saw. As it could knock you on your ass w/ 1-2 tokes and you could see the crystals,the rumors that it was treated w/ hash oil,opium etc began to fly. How else could mere weed knock those he-man tokers on their butts with a single hit?
Now the fake Thai Stick made in the States circa '74/'75 was generally treated with hash oil or embalming fluid,but you could spot that crap in a second. It was stuck on BBQ skewers with sewing thread. It would get you high as a kite but it was real geeky buzz.
There was a shorter stick that came out of NorCal in the late 70's. Fluffy,untrimmed,unseeded bud slightly better than the better commercial Colombian on the East Cost. It weighed in at about an 8th of an ounce and ran about 5 bucks a stick.
Now,the Buddha Weed I remember from that era wasn't treated with anything. It was just a good strain of weed from up near the Thai/Burmese border. In fact it was often called Burmese in the late 60's/early 70's and carried a hefty price for those days,40-60 an O Stateside,however it wasn't as strong as stick weed. The Thai Stick came in at 14-16 sticks per O and sold between 150 and 180 bucks an O in the States.
If the Buddha the guy above ran into was treated,I would suspect heroin as it's dirt cheap in that region.
Thai Stick was more about the way quality cannabis was packaged and presented in SE Asia at that time. You could get it all over the region,except oddly enough in most of Thailand. With exception of a couple of guys from the north,I never met a Thai who knew what the hell it was.
The last honest to God Thai stick I ran across was from a Merchant seaman buddy who picked up an O in Hong Kong circa '81. I don't know if it exists now,I hope it does. The rumor is that Trainwreck,is the old Thai Stick strain but who knows?