The 2001 book "Gunsmiths of Bedford, Fulton, Huntington, & Somerset Counties" by Whisker and Yantz indicates that Henry Griebel was identified as a gunsmith in the 1834 to 1836 tax lists of Stony Creek Township, Somerset County, Pennsylvania. I did not find Henry Griebel in transcripts of the 1830 or 1840 censuses of Somerset County, Pennsylvania.
L. Dietle