You are correct in regard to Conrad Drunert. The Republican story referred to "wounding three of the Colonel's men, one of them seriously" during the Briscoe Farm fight. Then the History of Warren County's account of the Briscoe Farm Skirmish stated "In this fight private Conrad Drunert, bugler of Capt. McFadden's company, was seriously wounded." Knowing that one of the wounded afterwards died, I had incorrectly extrapolated that man to have been Drunert. I should have known better, because elsewhere in my extensive files I see I have Drunert having been been wounded and captured by Marmaduke's forces outside Patterson on April 20, 1863. Third time being a casualty proved to be the final time for him--that Rocheport locale for Drunert's death you mention involved the Goslin's Lane fight against Tom Todd and George Todd (who had recently taken control of Quantrill's command).
Of course the published bio of Nathaniel Drunert mentions that Conrad was killed during the war while serving in the Fourth Missouri State Militia Cavalry, which only goes to illustrate the nature of the many pitfalls that lie in the path of researchers of the war, given that the unit Conrad was serving in on the date of his death in 1864 was in fact the Third Missouri State Militia Cavalry.