I found this in the basement of the house I inherited http://imgur.com/gallery/wjakAF9
It seems it was mass produced for people sending notes when the Reagan was shot in 1981.
Here is a newspaper story from Sumter, SC where a 10 yr old sent a note to Reagan. It has a picture and quotes the same words as in your note.
Here is another newspaper story from North Carolina about a lady that sent a note and it quotes the same message as your note.
It looks like yes, it was mass produced. Reagan was shot March 30, 1981, and that letter was mailed May 13, 1981. There were a lot of people sending Reagan "Get Well Soon" letters throughout April and May 1981, and beyond. The signature is most likely an autopen. The autopen is a gizmo that mechanically produces blocks of text and signatures that look like they were written by hand. In this case, they had an autopen of Reagan's signature and added it to this letter. Reagan wrote using the autopen gizmo and then thereafter, the autopen could reproduce his signature until it wore out. Autopens can only write on single sheets of paper. Here's a collection of different Reagan autopens. http://4.bp.blogspot.com/-BnHey-FXMpE/TaRgIFyIe7I/AAAAAAAAA54/cCWLppL38_U/s1600/ReaganAutopen.jpg None of those examples look like that signature you have, though.
