Your problem most likely won't be with the African countries. Problem will be with the good old USA. I recently read on another forum about a guy wanting to take his suppressor to RSA. After much research he found he had to get special approval from our wonderful gov't to export then bring them back to the US. Having a Form 4457 for the suppressor wasn't enough.
I would agree the 4457 isn't enough, one would need to have a copy of their AFT Form 4 which you are required to have when in possession of the can. I recall this requirement mentioned before and always have copies in my vehicle. I haven't been 100% successful coming back into the US and had a trophy shipment illegally confiscated at the Denver Airport. I was forced to pay for an overnight shipment of my trophies to Seattle. Next day I got it ironed out and my trophies were released. I came away with an apology but no refund.
Since other hunters aren't chiming in with successfully traveling with cans then I'll not risk travelling with mine.