The back of this particular series of drafts has no printing. Most have the endorsement signature of the payee on the reverse.
The format (design) provided by the original poster was used between 1849 and 1858. It was replaced by the following design, which was used between 1858 and 1865, and it had some additional printing on the reverse. This image is not mine, harvested from
ebay.
Front...

Reverse...

Another variant of this draft was used by the Post Office Department beginning in 1837, and continued through 1849. It looked like this.
Front....

Reverse...

These appear regularly on
ebay, and most of those I have seen and recorded during the past decade are from a small number of post offices. Newark, NJ, New Bedford, MA, Hartford, CT, and Middlebury, VT are the origin of some of the more frequently seen examples.
I suspect that the postmasters at these offices preserved these drafts in their archives rather than destroying them after the designated period of retention.
MikeL