uhh, I thought the P95 came with a built in rail. If your asking has anyone successfully attached an accessory to it, then yes. The one I had, wore a M3 tac. light on it.
I recall seeing where someone had attached a rail to their non-railed P95. I don't know if it was this forum or elsewhere though. If I come across it I will post a link.
Simplest thing would be to track down one of the 2" rails that come with the ATI stocks and bolt one of those on the bottom of the older P95 polymer frame in front of the trigger guard.