"Is this a Yamaha V50 Patch?"
I don't know. It was the most over-used and well known patch of the DX7II, as far as I know. The first DX7 had the E.piano_1 patch, but that one is not so bright and Whitney Huston-ish! Anyhow, the Fulltines patch is a must for all DX7 players, IMHO!
/BR
Michael in Scania
Edit: SynthMania on the DX7 E.PIANO_1 patch
"THE MOST FAMOUS PATCH OF THE '80s!!!!!!! Used by EVERYBODY, the fabled INT11 preset has become a standard sound (aka "FM piano" in all modern workstations, of all brands. It was manipulated in many ways, but the typical add-on was a wide chorus, to achieve that polished, professional sound. Mixed with a regular piano sound, it became the "L.A. piano", a standard for mid-80s ballads."
http://www.synthmania.com/dx7.htm