SP only has one font available for SA profile keycaps at the moment, called Gorton Modified and it's an engraver's line font, similar in style to Arial and Helvetica. They have at least two different sizes available for the alphas, but I'm not sure about the other caps. Retro SA has slightly smaller legends:
and 1976 is a good example showing the larger version:
We (C.Q.Cumbers and I) want to add another font for SA sets and will start a thread about it soon, but it will be a long process requiring a lot of fundraising, since the legends cost $50 each to cut and you need to cut about 110 to support a full 104-key layout including ISO and Winkeyless options. You can see what we hope for it to look like in the Classic Space IC thread. It'll be a more "modern" option and hopefully be a popular alternative to the stock one.