Is the stalk from BM as well? To me it appears the two are not compatible. ZenixNet, if you are referring to the two holes in the RF pic when it is taken apart, that is the top and the holes are for the LED lights.
I have a bobamaker stalk and range finder from him. His range finder is only compatible with his stalk only. You might be able to rig it together if you can get it apart but I tried to take mine apart with no success. But if you do get it apart it looks like you could drill two holes and screw the RF on then.