Brian, the surrender at Camden and Pine Bluff referred to is actually the parole of the members of the regiment. For several months prior to the end of the war, all of the Arkansas infantry regiments had been pulled from the State and encamped around Marshall, Texas. None of those regiments actually surrendered -- they were included in the general surrender of the Trans-Mississippi Department on May 26, 1865. The plan was to send Union parole officers around to the various camps and parole the troops; however, when word of the surrender was received, the regiments simply disbanded. There are accounts of a few companies which maintained their organization and marched back to Arkansas to be paroled, but the overwhelming majority simply left and returned individually or in small groups. Quite a few (mostly Missourians) were paroled at Shreveport, Louisiana, since the United States agreed to provide them with river transportation to their homes. Many, if not most, of those paroles found their way into the soldiers' Compiled Service Records. Not so with the Arkansas troops who traveled to Camden and Pine Bluff to be paroled. I don't know where those parole records ended up, but I've never run across any.
Anyway, as a purely technical point, Polk's regiment did not surrender at Camden and Pine Bluff, but from accounts it is known that many were paroled there, which is what the biographical sketch probably meant.