Close but no cigar. Two out of 3 Roger ... your man died in 1916 and came from Pennsylvania ... just like the person I want.
Unless you are 100% sure that Gregg did not vote for Lincoln in 1864 I'll stay with the name I have.
This person was born in the US. Marquis de Lafayette was not of course and anyway he died in 1834.
“The honest man, tho' e'er sae poor,
Is king o' men for a' that” Robert Burns