The engine in the Generac TXP/Dometic DTXP generator is a Briggs and Stratton, but B&S only supplied the short block and heads, so it isn't covered by any B&S manuals. The short answer to your question is that there are no points in that engine, the ignition is electronic.
You can find a complete service manual by searching online for TXP and the filename "50357.pdf". One place I found one is:
http://www.gen-parts.com/Manuals/50357.pdf
I have one in my old RV, and I've been told that parts for the TXP are getting very hard to find.