Thinking logically here based on the information given.
1. It says the speed brake lever won't move beyond the flight detent. Surely that answers your question main question.
2. There is no note in the QRH because the flaps up checklist would have penalties for landing flaps up and those penalties would necessarily include the loss of full spoiler deployment. In other words, the loss of spoilers is an inevitable consequence of a flaps up landing so there is no need to make specific mention of the spoiler penalty.
I don't fly any Mk of 737 so could be way off base.