Of course many units entered state service afterwards. Efficient or not, every Southern governor took steps to maintain a military force that would answer to him rather than Confederate authorities.
Records of companies assigned to those three regiments should include testimony concerning prior state service. The 7th Mississippi Cavalry was one of the units mentioned. The following comes from Dunbar Rowland's history of that unit, AKA Ham's Mississippi Cavalry --
Major Ham's Battalion, entitled the First Battalion, Mississippi State Cavalry, was organized at Guntown, May 18, 1863, including Companies A, B, C, D, E. Companies F, G, H, were added during 1863. "It appears that by an agreement understood by the President, the Governor and General Pemberton, the upper tier of counties and one-half of the second tier, being considered outside our military lines, were exempted from conscription, and State and partisan companies were authorized to be raised and the conscripts in them were not to be interfered with." (S. D. Lee, report September, 1863). The Governor stated that the men were mustered in for twelve months, but their rolls were never verified by Confederate States officers. Many of the men also attended to their home duties, and threats to conscript them, and the general uncertainty of their enlistment did not encourage them as efficient troops. They were unpaid for months also.
In early 1864 the battalion reenlisted in state service, transferring to Confederate service in May 1864.