1868 "Report of the Adjutant General of the State of Indiana, vol. xviii.--1861-1865." (Indianapolis: Alexander H. Conner State Printer), pp.113:
Gapin, Robert (no company listed)"Killed at Fredericksburg, Va., Nov. 9, '62" and on page 486 ("Roll of Honor") this information is repeated with the additional information that Gapin was in Co. I. There's a new book about Co. I very recently announced on this Message Board which might contain additional details.