It's true that you would not HAVE to provide a notice of the hold you placed. However, both for the sake of consistency and for customer relations, I believe a hold notice is appropriate.
The length of your hold should not be an issue under Regulation CC. I am not aware of any state rule that would address your question.
A comment: Obviously someone in your bank felt there might be a problem with these savings bonds, although the only description you gave is that they were "stale dated" and that there were a lot of them ($48,000). Did you consider at the time the alternative of forwarding the bonds directly to the Fed for payment and crediting your customer's account only once you had received good funds?
John S. Burnett
Fighting for Compliance since 1976
Bankers' Threads User #8