David Yoho
Ken, I guess I assumed the brad nailer trigger valve was like the finish nailer trigger valve. Looking at the parts diagram it's different. It does the same thing by passing air through to fire the mechanism but the 18-gauge gun has a group of parts where the 16-gauge has a trigger valve assembly.

As long as your gun fires when pulling the trigger, I'd say you don't need the parts. However, it might not hurt to have them on hand since some of the PC parts for their nailers are becoming not available.

Your call.