My personal view is that all the overprinting has achieved is to deface the original cover. Furthermore the addition of the SA images most certainly does not result in an SA related cover. The production of such items fills me with horror as theoretically it is possible to overprint any cover in this manner in order to produce a supposed SA related item. The mind boggles!
I wonder too about the knowledge of whoever overprinted these covers as they claim that the images show the SA Founders. Upon close inspection the images are actually of William Booth and his daughter Evangeline. Whoops!
Is this cover a deliberate attempt to deceive? Probably not. It is not however an original FDC and I am sure that there are collectors who will be deceived into thinking that this cover is totally original.
To produce an original SA cover is not that difficult. All that is required is a purpose and a little imagination. In my humble opinion the production of covers such as the one below can do SA philately nothing but harm.