ECI and MILLENNIUM CYLINDERs questions?

I'm going to look at a Continental O-200 engine tomorrow. The owner says it had new ECI cylinders installed a couple years ago, however, the pictures show Millennium valve covers. I know you can put any kind of valve cover you want on them. How can you tell the difference between ECI and Millennium cylinders? Also, I seem to recall some problems with ECI cylinders awhile back. How can I find out if these cylinders were part of the problems? Any info is greatly appreciated. Thank You.

New cylinders generally don’t come with valve covers so they probably got reused.

ECI has had a long history of cylinder problems. I don’t think the O-200 was subject to any of their ADs but they did have problems. That’s not necessarily a deal killer (depending on the deal) but should be factored into the price. New Continental jugs will set you back about a grand each.