There is a book called Names in Stone which lists the tombstones of Frederick county until around 1950/60.
There are a couple of Wetzels at Liberty Chapel Cemetery, the one I can find is William G 1871-1934 and his wife Sarah E 1874-1923. I didn't see any others but I could have missed it.
If you have a paid subscription here then you can find a copy of it in the Card Catalog.
This also seems to be the same cemetery as "Union Chapel Cemetery" on find a grave, most the stones seem to have been transcribed as well.