deal
Without the scope, that is still about $100 below retail. I'd call that a deal if the condition is as clean as you say. The Ruger American is getting lots of good press as a tackdriver. A "new" Redfield as made in UsA again (see below) sells $175-200 and would further the value of the deal. If it is an older Redfield, read on.
The Redfied scope is a bonus that could be a real plus or just so-so. A "Denver" USA Redfield is going to be an older scope,.... and could be much older. They were well respected in their day, and many are still afield, ( I have one on a rifle myself) but a Denver Redfield will date back to 1998 or before. If it is a 1970's or 80's model, you are looking at an optic that is 30-40 yrs old, and glass quality/coatings though not poor, is not up to par with a decent current scope. Not unusable, but not cutting edge either. You could have an issue with the seals as well. If you hunt an older Redfield (or any older scope for that matter) realize the seals could go south at an inopportune time. In '98 Redfield closed after EPA issues I think.
For about 10 years, till 2008, the Redfield name was still out there, but the scopes were little more than imports and about the equal of all the other Asian import scopes like Simmons, Tasco and Bushnell. In 2008, Leupold bought Redfield, and the scope is made in USA again today. Most early scopes are Denver or USA marked Current Redfields that I have examined, as run by Leupold, have a big Red R on the side, and there is no missing it. I put the current Big R Redfields in the same class as the Burris scopes and entry level Leupolds and Nikons, and would not hesitate to hunt one, but I dislike that big R lablel on the side.