That knock box is definitely old school. I'm sure very few were / are still in circulation. If you trace the wires, you will probably find one that's tapped into the ECM harness, knock sensor wire. The same way you would tap a Caspers knock gauge and audible alarm.
I concur, a pic of it would tell us more about it. I don't see any issue with it.
But it does bring up another point, having the Scanmaster on the radio pod, makes it very hard to watch your O2 mv and degrees of knock, while flying down the road checking the tune. Kirban sells a steering column mount for the Scanmaster as does another member on here, if you didn't want to mount it on top of the dash.