Yes the seal has similarities to the coin. But that would make sense if the coin uses an official emblem of the Republic of Kenya. see http://allthingskenyan.com/currency.html
But what is the size of the coin supposedly used to emboss the paper compared to the seal in Orly’s photograph? Do we know the paper size that would have been used for the Certification in 1964? What about size of the coin?
Also how does one emboss with a coin.
I know you can fake it in Photoshop.
Try it.
Take a coin with good sharp features and place a sheet of paper over it.
Experiment with pressure, rubbing and striking with soft objects.
I tried this with a half dollar and some other large coins. It actually works pretty well. You have to be careful around the edge if the coin edge is sharp. But with a little practice you can get some pretty good results.
If a person has something resembling a press in their home (a bottle capper, garlic press or even long jawed pliers) they could probably get more consistent results.