For some reason, in this specific section, when members search for the Idaho prefixes it returns results from Oregon. It also happens with a single Oregon ad in a couple other sections.
1. Go here: http://www.northwestfirearms.com/forums/part-accessory-classifieds.21/
2. Click "Idaho" where it says "Quick Search: Oregon|Washington|Idaho".
You can also go to the standard advanced search, click the Search Threads & Posts, select the Part & Accessory Classifieds section, and click the first four ID: prefixes.