An article by Stuart L. Butler in Prologue: Selected Articles, Winter 1991, Vol. 23, No. 4, was entitled "Genealogical Records of the War of 1812." [A variation here]
Adjutant General's Office (Record Group 94) was mentioned in the article. [Consult Fold3.com for records online]
Perhaps the most genealogically rich records for this period are the pension application files in the records of the Veterans Administration (Record Group 15).
"...Index to War of 1812 Pension Application Files (M313, 102 rolls). [NOTE: Some of the M313 records have been placed online at Fold3.com]
Often overlooked, but potentially useful, are Miscellaneous Manuscripts of the War of 1812 and its accompanying name index.
There are several National Archives publications that researchers should examine before using some of the records described herein. National Archives Microfilm Resources for Research: A Comprehensive Catalog (1990) [see article for others].