I have the Federal Pension Records of a Confederate soldier from Mississippi who was captured by Union forces in GA and sent to Rock Island POW camp in Illinois where he joined Co. G. US Volunteers and the company was sent to Colorado to deal with Indian problems. In his old age, he was awarded a disability pension from the US government; when he died, it was awarded to his wife until she died.

So it seems that "galvanized Yankees" were eligible for Federal Pensions. I have not heard of family accounts of his service as a "galvanized Yankee". He was buried with a family grave marker, not a CSA marker, but that was the same for one of his brothers who served in the CSA until surrender; another brother of the same unit who served until surrender and does have a CSA marker. My interpretation of CSA grave markers is they are on graves of members of families who had financial stress.