There is a G.A.R. section at La Vista Memorial Park in National City, California with a number of well-kept in-ground graves and a monument to the men buried there.
Out in the "non-endowment" area of the cemetery are several stones that bear notations that commemorate Civil War veterans. The ones I saw and photographed (before my camera juice ran out today) were these:
1) David Palmanteer:
2. Leonard F. Davis:
Leonard F. Davis
Sarah E. Trimble
3) B.F. Fletcher
I will go back to La Vista soon to see if I can find more Civil War soldiers gravestones and photograph the stones in the G.A.R. memorial area.