I got my linear rails HGR20 and guides HGH20CA-ZA, there is a little issue (not sure if it is a problem).
I can not find a indication saying its HGH20CA-ZA (ZA stands for medium preload). As you see in the picture it says only HGH20CA. Where would i see the ZA part.

Second it seems the linear rail HGR20 has a slight bend on it, is that normal. Later when i mount it would that bend be removed from clamping down with the screws? I am just wondering. Or does it have to be straight? Please see image as well.