The main physical evidence to look for are shatter cones (I've learned a lot in 24 hours!)
http://waittfoundation.org/ludovic-f...n-remote-congo
The structure is in the middle of channel country and the side that has been eroded away is certainly in keeping with the direction of water flow. The fact that it is in the middle of a channel makes the hope of finding meteor fragments very low except for on the structure itself, and there are plenty of alluvial sediments obscuring any underlying structural evidence.
Ultimately it may be a job for geophys or crystallographers. Which ever way, to get into the Earth Impacts Database it needs to have a published paper describing it.
Alternatively, I could just add it to Wilkipedia which makes it an indisputable fact for 99.999% of the population
