The latest documentation I have is for a 2016 370z, and I don't think Nissan would have changed anything since. Based on the ROM you posted, your 370 is from 2017 and I would expect it to be the same.
The K-Line is still on pin 7 of the OBD connector and goes directly to pin 117 of the ECU. Nissan sometimes calls it "K-Line" and sometimes calls it "Data Link Connector"
Try this test:
• With the CAN bus not connected, log data and look at the time between samples. The UpRev log shows time in milliseconds.
• Hook up the CAN bus and run the data logging program again.
Since the K-Line runs at 10,400 bits per second, and CAN bus runs at 500,000 bits per second, I would expect the time between data to be much faster with the CAN bus.
I suspect the UpRev software checked the CAN bus for communication, didn't see it and "failed over" to the K-line.
This would allow them to use the same code for older cars (before 2008) that don't have CAN bus.
I look forward to your test results
