I don't have a 4K monitor attached, but the question is interesting for me. I am also thinking of switching to a 4K monitor, which is why I did a little research. You'll find what you're looking for on Lenovo's homepage:
https://www.lenovo.com/ch...DisplayPort: 3840 x 2160 @ 60 Hz; HDMI: 3840 x 2160 @ 60 Hz; Bundle DisplayPort 1 & DisplayPort 2 to the monitor: 5120 x 2880 @ 60 Hz; "Maximum resolution" refers to what can be supported by the dock. Actual resolution will vary by laptop.
Answer to your question according to my research: Yes