I was not aware there were notes circulated. I thought it was just the coins. Yes, the deposit receipts could have been considered a silver-backed currency. (Still not affected by the revaluation, since it still represented a fixed amount of silver.) It should be noted that if he hadn't put the word "Dollar" in there anywhere, most likely nobody would have cared.
His problem was that he made it look too much like the US's monopoly money.
His problem was that the PTB were able to convince a jury that he made it look too much like US currency, not that it actually did. They were able to convince 12 ignorant people that the term "dollar" wasn't generic, and that alone would then imply that it was an attempt to 'counterfit'. I just think it's sad that, in our modern world, it was so easy to randomly find 12 people that ignorant. That wouldn't have been true even 100 years ago. The average illiterate farmer from Kansas knew that the term "dollar" referred to a silver coin of particular weight. For that matter, there was an ongoing public debate about the virtues (and vices) of the bi-metallic standard, and the book The Wizard of OZ was written as a farce to make fun of it. (Originally, Dorthy wore silver shoes to walk on a gold brick road)