Probably more are uniface in my guess than double sided. Depends on the issue, both were printed. I have never known the rhyme or reason why different series were one sided or two. The paper is a dead giveaway though. That is old newsprint that yellows and cracks like that. That kind of paper was not used for bill printing. It might yellow with soiling (different look), but that crack would not happen.
Yes, I have a small collection of CSA Notes. This one has an error on the hand written serial number. I have another bill that also has a printing error. This bill has writing and interest paid stamps on the reverse. The obverse is slaves hoeing cotton. The reverse is hand written between the interest paid stamps "Issued Monroe, LA April 17, 1863.
Interesting note. I got a group lot at HA some months back with three examples. one of I believe only 2 as far as I see depicting slaves on CSA notes. I do not show them to most people unfortunately for fear they think by owning them I am promoting some political idea. I like the grumpy old cuss on the lower left. Imagine choosing this as your likeness to be printed. Yikes!
That grumpy old cuss (John C. Calhoun) didnt have a choice as he was long dead before the notes were printed.
The 1864 notes were referred to as the bluebacks because they had a printed reverse - but the 50C and $500 notes did not have printed reverses - go figure the highest denomination didn't have a printed reverse for security.