I agree with both John and Allan on LE. Casinos are free to remake their house chips whenever they want to. "Limited Edition" implies they won't make more than some set number. We all like it best when they put that number on the chip, but there's no rules. Take the Fitzgeralds Reno chips in this scan for example. The casino has essentially promised the collector that there were only 100 $100 chips and 400 $25 chips made, and they won't make more. I don't know what they're promising us about the $5. If the quantity is sufficiently large, "limiting" it has no real value. It's called marketing hype.

Commemorative implies the chip commemorates some event, person, whatever. Some chips appear to commemorate the fact the chip designer got up one morning and felt like drawing a picture in a circle. So, the two terms mean different things, but generally both apply to chips produced specifically for collectors.