RugerSociety.com

Bennett,
You beat me to the RENE. The barrel doesn;t have the taper like the earlier models so I would say that is a heavy barrel. The heavy barrel in a Six series isn't like the full shroud GP100 (which to me would definitely be classed as a heavy barrel).

The early models had a definite taper to the barrel and you could see it pretty clearly when focusing on the "rib" on top of the barrel. If you put a standard amd heavy barrel together it is also pretty noticeable. I'll see if I have a picture comparing the two and if I don't I'll take one.

The oddity is not having the rollmark on the right side, I wonder if it just slipped through the cracks.

Ron, thanks for the pics and explanation on the barrel and I believe your right about it having a heavy barrel. As far as I know the only handgun Ruger ever put out without the model name on it was the Standard pistol. It very well could have slipped out without the marking. The seller said that Ruger told him it was shipped from the factory in August 1984 however the serial number indicates 1985 manufacture. Would love to know the true story on it but as you know these things happen from time to time. I just grateful that I found this oddity.
Bennett

Ruger did a couple of commemoratives, the FBI commemorative and the Alabama Sheriff's Association Commemorative.
Both had the large "RUGER" rollmark on the right side of the barrel presumably because each had the FBI and Alabama statement on the right side of the cylinder frame where the Ruger Security-Six would normally appear.
I know at least the FBI gun also had that large uncheckered walnut grip.
Chet15

The does look like one of the FBI commemoratives without the FBI seal on the cylinder frame and the writing rollmarked on the backstrap. It does fall in the s/n range that you've listed in R.E.N.E.
Bennett