No reply to my email about the scanned maps, but the GeoTiff maps available here:
http://svinetfc4.fs.fed.us/visitormaps/
seem to be "Open Source". From what I could find, they seem to fall under the same useage laws as the USGS data (I would think the scanned maps would fall under the same regs, but I have no confirmation of that).

This is what I found by clicking around the site:
"Information presented on the Forest Service website is considered public information and may be distributed or copied. Use of appropriate byline/photo/image credits is requested."

The tif files are in NAD83, once reprojected to WGS84, they only require 2 points in RMP maker to calibrate and they are very accurate.

They aren't very detailed for hiking, but they are good for driving and OHV use as a companion to the printed version.