Probably not. Processor vulnerabilities have the perpensity to affect most OSes because they're often pretty fundamental flaws in the basic CPU security mechanisms when discovered.
The thing about the BBP is that it is a second computer running its own proprietary OS (typically an RTOS) to handle the RF modem. The phone's main OS typically has no visibility into that second computer, even as root, but the reverse may not be true.
So I was wondering if any of Google's efforts to increase security can mitigate attacks that might come through this particular channel that lurks, Kuato like, just out of sight.