a gift horse

English as a Second Language English Vocabulary, Grammar and Idioms
1
  1. I’m never one to look a gift horse in the mouth.
    1a. I’m never one to look at a gift horse in the mouth.
  2. I’m not one to look a gift horse in the mouth.
    2a. I’m not one to look at a gift horse in the mouth.
  3. I wouldn’t look a gift horse in the mouth.
    3a. I wouldn’t look at a gift horse in the mouth.
    Please check and correct the above sentences.
    Thanks.
2

‘look at’ is incorrect with that idiom.