Lee - There is quite a bit of correspondence at the following link that mentions bonds such as these. By using my browser's "find" function, I found 51 cases of the use of the word "bond". Sometimes the word was coupled with "of sufficient surety". I am assuming that these were not actual cash bonds, but more of a promissory nature in case the accompanying oath was broken. But that's just my reading of it.

http://www.simmonsgames.com/research/authors/USWarDept/ORA/OR-S2-V5U.html