I agree many large mailing houses do attempt to mimic legitimate postage meters, with just enough of a difference to avoid any copyright infringement, although I must admit the eagle head shown in your example is very close to that used by Pitney Bowes.
I thought it would be fun to compare your example side-by-side with a legitimate Pitney Bowes indicia and came up with this:

Note the longer feathering (A); no open line at upper right corner (B); longer beak shown in the PB example (C); thicker line at lower right corner (D); and slightly different shaped curve at (E).
Close enough that copyright infringement of the eagle could be an issue, but I'm sure PB chooses their battles carefully as to what may or may not infringe on their image v. the legal fees to fight any court battle over it.
Beyond your scan, there are other mailing houses that mimic other legitimate postage meter designs, too. Take for example this Data-Pac meter comparison. The left design is that used on a mass mailing piece; the right design is the legitimate Data-Pac Postage Meter indicia:
