Appears to be an honest example. As far as I can tell, this is a 145.022 from 71, 74, 76, or even 78. 145.022 being the reference on the inside of the case back; the year it was produced will follow that ref. number to confirm. In the 70s, those were the years that were stamped for this ref. The serial number is located on the movement and will also help date this watch. The reason I date it from this period is because of the tall TACHYMETRE lettering without the accent over the e. This, in combination with the domed dial, rather than the earlier 321-style stepped dial make me think it is one of the latter. It appears that all of the tritium has been cleaned off of the plots, but the watch looks to be very clean otherwise.
If you haven't already, take a look at speedmaster101.com, tons of info over there.
-ct