Dots on the same place for the same cards happened pretty often for the Base Set. Personally I’ve never seen the black spot in this position for Blastoise before, but I don’t see any reason why it would be fake.
Some examples of other ink drops that happened on multiple cards:
Blue dot Vulpix:
Which is also available in 1st edition:
Black dot unlimited edition Charizard, on top of the Nintendo at the bottom:
Red dot Blastoise above the Water Energy on the left:
Clefairy with a pink heart-shaped error at the top (although I’ve heard rumors someone made and spread these errors themselves):
Jungle Pinsir 1st edition with a weird spot above the 1st edition symbol:
“d” edition Jungle Butterfree (not really an ink drop error; but more a dirty printer that made these “d” errors on the same spot on every Jungle uncut sheet):
Fossil Krabby set symbol error (again, not really an ink misprint; a part is missing from the Fossil set symbol):
And I could give more examples. Anyway, it’s a pretty common occurrence. These days ink misprints are still pretty common to find, but they’re usually one-time errors from ink dropping or something. These errors above are always on the same spot for multiple individual cards, which means it was a defect in the printer itself rather than ink leakage.
Anyway, none of these are very special or worth much more than their regular version. As mentioned by Gary, ink misprints usually draw away from the appeal of a card. Although misprint collectors still like them. I also have a few Pikachus in my collection with ink drop misprints, but those are one-time errors as far as I know. I also once pulled a Delibird with yellow ink dropped on top of it. Both I’ve mentioned here.
Greetz,
Quuador