Peggy,
This is a long shot - but I have a Thomas Robert McGuire in my family tree who was in Minnesota for a time after the Civil War (1866) but for how long I don't know. He later returned to Indiana and died there in Randolph Co., IN in 1910.
This Thomas had two sons -
1) David Sherman McGuire -b 1865 in Randolph Co.,Indiana but who came to MN with parents, ended up marrying in Indiana then living in Los Angeles, Los Angeles Co., California and was buried in Ingelwood, Los Angeles Co., CA in 1942. I have David McGuire's family and he had at least one son who was born in CA and one son that was married in Minnesota.
2) Lewis B. McGuire -b: 1866 in Stearns Co., MN. (This is how I know Thomas R. McGuire was in MN for a time).

How this all may shake down - I have no idea !!
Just thought you may get some kind of lead from this info in connection to the 1881 Minnesota Land Grant paper you found in CA.
Good Luck,
Judy Mills Boie