I wouldn’t say they are too rare. Although not too common there are quite a lot of 115 Hoovers out there. I found mine at a barn sale for $2 in really nice and all original condition. Believe it or not the brush strips are still perfect!
I think he means "in the wild". Goodwill, salvation army, etc. The oldest vac I have ever found "in the wild" is an early 80s straight suction douglas handheld.