Hello and thank you for your question.

From what I've read on the Rode website, the transmitter in the Wireless GO II kit has a 3.5 TRS jack.
If you want to connect your SmartLav+, you'll need to buy the Rode SC3 TRRS - TRS adapter.
I had this problem with the old version of the Wireless Go.

I hope I've been helpful.

Best regards.