Yours are from the 1913 issue of South African revenues.
A very similar design in a somewhat smaller format was issued later, starting in 1931. Here is a visual aid that includes a basic, definitive postage stamp for comparison.

The 1931 and following issues contain a tiny year under the neck of George. The earlier issue does not have a year incorporated into the design.
You have Barefoot 1, 2 and 9 (in order of value, or right to left in your scan). Not terribly high CV, and the condition is rough. These are not uncommon, so condition still matters quite a bit, in my mind (even though I give revenues more of a pass on condition than their postal cousins).