Sorry for the delay in responding to your inquiry. It's been extremely busy over this holiday season. I'm still compiling my info on Buster's(Clarkson's) Bn. Hopefully, in next few days I'll post it.

Where does everyone get M.W. Buster being a Major at Wilson's Creek? His position was adjutant, and it's extremely unlikely for a Major to hold such a position within a Regiment. Normally, this position was held by a Captain or even Lieutenant. The Major for Clarkson's 5th Inf Rgt/8th MSG Div was a Alexander C Lemmon [pg 236 of Price's Lieutenants].

From "Sterling Price's Orderly Book, 1861-1862", transcribed by Richard C Peterson:

Gen Order#33,dated 31 Jan 1862[on pg 52]. In Para. III-"M.M.Buster is hereby appointed, subject to the approval of the Governor of the State of Missouri, Quartermaster and Commissary for Headquarters with the rank of Captain...."

Earlier, from an order dated 27 Dec 1861[pg 152] Cpt M.W. Buster appointed inspector of pickets and assigned to duty at HQ.

On pg 110 has Buster's resignation dated 16 Mar 1862.

From index card filed at Mo State Archives, Buster's term of service expired 25 Dec 1861(he'd been elected adjutant 12 July)

From private correspondence with Ms Nancy Bowen, an 11 May 62 Special Order#1(Clarkson's Bn) appointing Cpt M.W. Buster adjutant of unit.

From a CSR card for Buster filed with Clarkson's Bn states in remarks section-"Assigned to duty as Lieut Colonel Aug 5th"

I myself haven't found any indication he ever held the rank of Major. If you have material which states otherwise, please let me know so I can correct my research.