Will a Reverse Polarity (RP) connector fit a regular connector ?

No, they won't fit together

The inner RF pin genders will be different and they will not mate together.

Reverse Polarity (RP) Connectors:
Male Connectors will have Female RF pins - Female Connectors will have Male RF pins

Standard Connectors: Male Connectors will have Male RF pins -
Female Connectors will have Female RF pins

The important thing to take away from the above is RP or Reverse Polarity Connectors will NOT connect to Standard Connectors due to the inner RF pin differences.