I have viewed the card for Montgomery, S. G. previously...
Per data from the listings of the Lobb Cemetery:
Montgomery, Samuel C., 21 years, 7 months, 28 days, d: Jan 19, 1863
A Photograph of the new stone shows:
(AT the top) Maltese Cross with a wreath contained therein
Samuel C Montgomery
PVT Capt Quantrill's
MO Partisan Rangers
Confederate States Army
1842 Jan 19, 1863