How to identify macbook pro touchbar

Hi I know the macbook pro touchbar first release was a 2.9ghz and that it got a bump to kaby lake 3.1ghz correct me if I’m wrong but how do I know if the model is the first gen or the second one with the kaby lake proccesor? Since I‘m looking in to buying one and where I live they usually takes a long time to update the electronics and I don’t want to be screwed with a older model 😟. Thanks!