That is a restamp absolutly.
I noticed the trend a few years back, that people were stamping these.
It seems the 346 masters were used all the way through 1978, without a "thumb" pad, and no bleeders.
One day on ebay, I looked at a horrible pad surface, and bleeders that were not in the right place.
I started watching more carefully at them, and noticed more and more restamps.
The hackers, are getting much better since back then.
That surface is too smooth, and the WT should different then that one.
I have 4 or 5 real ones, I will get a real good picture, as soon as my camera comes back from the shop.
(any day now)