I would be reluctant to pay over face for a well circulated 1954 note which is apparently missing the serial numbers. Logically, is it possible for a note to remain in circulation, passing from hand to hand until it is well worn, if it has such a prominent error? I don't think so. Somebody would have put it away before it had received much circulation.
Every well circulated note with no serial number that I have examined has had the serial number removed after it entered circulation. For the reason explained above, you would probably be safer buying a very high grade note; besides, a high grade note would be more likely to show the effects of the treatment it took to get the numbers off if it was a fake error.