Confused Booklet Bk49?

I have what I thought was a US BK49, containing four panes each of 24 1-cent (462) and 24 2-cent (463) stamps, first issued in 1916. On examination, however, I found that the 2-cent panes are actually 554's, issued in 1923. I assume a seller somewhere along the line combined the panes to create this booklet, but I have to ask: Any chance that the USPS did it, maybe combining left-over 1916 stamps with the 2-cent 1923 issues? For what it's worth, the booklet does not look like it was torn apart and re-stapled, and the staples themselves look identical to those in other booklets from this era. They're even tarnished. Thanks in advance to anyone who can advise me on this.

Are you sure the 462a are not 498e and thus a BK57 booklet?

That's it! Thanks so much, eyeonwall. Much appreciated!