I know that なめんじゃねよ means don’t fuck with me but does 舐めんじゃねぇぞ have the same meaning or not ? if not what is the real meaning of the sentence 舐めんじゃねぇぞ?
The only difference (other than the kanji being used in the latter) is the particle ぞ, which can be seen as a "stronger よ", so yes, meaning-wise they are the same.
Yes. It's yet just another variation of 舐めるなよ / なめんなよ