Now, Rod, as you well know, Japanese postage stamps, let alone revenues aren't my thing, so you'll naturally treat my remarks with great caution ...
My difficulty with these stamps as revenues is that Japanese
postage stamps of that era were all inscribed 'Japanese Empire':

These stamps, however, are inscribed 'Domestic freight ... company ... freight ...' with the ellipses standing for characters I can't make out. Here are the crucial first three characters, though:

If I didn't know that Forbin classified them as revenues, I'd unhesitatingly say they were private freight company prepayment labels.
Incidentally, the large character at the top of the stamps is the same as the third character in my 'Domestic freight'. It has a range of meanings associated with carriage and mail.
Edit: Having worked on the characters in the horseshoe a bit more, I can now make out everything except the last couple - I think. They read (right to left) Local/Domestic Forwarding Company Freight ...
I think Forbin is wrong, and these, on the face of it at least, are private freight company labels. However, having said that, a Google search didn't throw up the company name.