If you get a single bundle acl surgery on one knee and a double bundle acl surgery on the other could this cause any harm to the body?

No harm: You would be an interesting case control study to compare differences, but there is a chance that both would function equally well. Both techniques can result in success, and therefore, you might not expect any difference or harm. Since you know which knee had which tech., comparison may be biased.

No: There are some that say they can feel a slight difference between the two, but there is no harm at all.