I figured out why this is happening. SDM uses a file format called CVA, which is really just a text file with some identifying information about each package. Looking at the CVA for the Bluetooth driver and using my own machine (which was imaged via our current process), I found a dll that the CVA referenced but was not on the SmartDeploy-imaged machine. I copied that file over, ran SDM again, and it now lists the Bluetooth driver as up to date, as it should be.
I should be able to work around the issue now, as I imagine I can update the drivers in the driver pack to include any additional files that the CVA says are needed. However, the best way to fix this would be if these missing files could be included in the pack from SmartDeploy.