In Florida, we run a state series, and have CS 27's as the handout. Over the course of a year they tend to accumulate. They still have a ton of life in them and are great for weekly club races, If people don't sell them , they often get handed over to the younger racers. I wouldn't think twice about it, unless you're running at the top levels, and most tires will have a lot of life left, especially for the prices being asked.
"They may be toy cars, but I spend REAL money to race them!"- Racer X
"It's only a big deal if you make it one."