Chad's 4th revision lists the (previously) known ser. no. range for the "FBI National Academy 50th Golden Anniversary" Commemorative as from 161-25783 to 161-83046.
This example has been reliably reported to me as having ser. no. 161-24756!
"Hittman",
No, I think that the specially marked 6" stainless pieces were pulled off the line in small batches as the orders came in and as the engravers could handle them. The key is a Security Six stainless frame without the 'Ruger Security Six" marking on the right side.
Not sure how they pulled the frames off the normal assembly line for this project.
It is my understanding that the Feds require that the ser. no. be put on a frame as soon as possible after it's made but have no such requirement for the model name.
Remember, the Speed Sixs and Security Sixs share the same ser. no. range. These are being made toward the end of the Six series double action production, about the time the GP-100s are coming on-line. I think there was less demand for the adj. sight gun at this time.
I think the number of completed FBI guns is small. The question remains about the number of 'unfinished' or 'blank canvas' guns. (Please see my other post )