Military Records - KNEMEYER, GARDSCHMIDT,RAHE, COMBRINK

Hello,

I'm trying to figure out where I can find military records
Specifically I'm looking for my GGGGgrand uncle Franz Henrich KNEMEYER. He has been listed in some IGI records as Franz Henrich RAHE.
He was born 4 Oct 1827 in Bockhorst #4, Westfalen, Preussen
Baptized on 6 Oct 1827 Evangelisch, Bockhorst, Westfalen, Preussen

Family stories say he was in the Prussian Army as a letter courrier.

He married Henrietta Friderika GARDSCHMIDT on 18 Jun 1853

In America he went by the name Henry Charles KNEMEYER.
His twin brother (my GGGgrandfather) Friedrich Wilhelm KNEMEYER married on the same day and location Wilhelmina Kathrina COMBRINK.

They all traveled together and arrived in America on July of 1853 so they must have left immeadiately after marriage.

Any help is appreciated.

Steven Knemeyer