I found out from the Lenovo forum that the reduced Android Market functions were a Lenovo implementation. They want you to use the mSpot app to purchase music and the mSpot Movie to rent movies. They would prefer you to use the Lenovo App Shop over the Android Market. That's why they are missing from their scaled down version of the Market app. I'm sure the parties involved are making money off this private arrangement.
You can download a new version of the Android Market 3.4.4 from here:
You will have 2 versions of the Android Market on the K1. With this version you can purchase music, but renting movies is still missing. I still prefer going into the Android Market using the web browser. You sign into your account and everything there and functional. This circumvents Lenovo forcing you to do things their way.