You may already have this info from the Missouri SOS site:
He is listed a Pvt P. F Lamear, Co G, 2nd Missouri Cavalry
"History taken from UDC record Missouri State Archives.
He was wounded at Memphis. 37 engagements from Elk Horn
Mar 6 1862 to Iuka Miss Mar 22, 1865 (this date is a typo I believe - JJR) This fight was the last shot fired by the command. Surrendered -- Paroled June 5 1836 (note another typo, number transpostion) at Columbus Miss." "History of Saline County, Mo. page 326"
2nd Missouri Volunteer Cavalry CSA has a long war record and a number of good descriptions of its history exist on the web.
As for a marker, good place to start would be to click on the banner at top of this page above and get his offical service record. Clearly he surrendered and paroled so there should be something out there in the Union records on him. The fact the SOS note refernces the UDC record indicates someone filed for membership or that the service record is in their records, try www.hqudc.org for more. You can also check with the Missouri State Archives for the UDC record as it looks like they had it sometime.