A review of the link from GregAlex shows 2004 as the year the "Certificate of Appreciation" first appeared in the format (titling) shown by the OP.
Quote:
May not be exact but is close, I believe they began to appear when the self-adhesive RW stamp versions first arrived.
I have now had time to review a Scott US Specialized and it lists the 1999 (valid to 2000) design as the first offered as a self-adhesive.