I wasn't around for the beginnings of either, but I was going to shows as early as 79 (my first show was Black Flag, GBH, Exploited, DK and a BUNCH of other bands on that Halloween)...
Metal was born when the elements of blues and rock were combined with classical...
Judas Preist is a GREAT example, if you go from their first Rocka Rolla, thru Sad Wings, etc... up to Hell Bent for Leather and Screaming for Vengeance, arguably Judas Priest's first two "Heavy Metal" albums... You can see the the transformation from a Progressive Rock band to acid metal, to heavy metal...
The "Slamdancing" or "ring around the rosie" of the old Punk days weren't anything like a Thrash pit. If anything, the latest "Hardcore dancing" done by HcX/HxC(sp?) or Emo type dancing is more like what a Punk pit was like back in the day.
Anyways, a good band to ask what it was like in the day would be DRI, who until Crossover was primarily a punk band, but liked what they saw and heard from the thrash crowds and music that it inevitably worked it's way into their style, as punk was dying and Thrash was coming up and strong....
So, I voted NO.