Continuity mistake: When Dale is talking about getting the silver medal, you can see that on the wall, near the bed, there is a wind catcher. Once Nancy says "If you say so, I was pretty drunk", the wind catcher disappears.
Continuity mistake: When Dale knocks John Redcorn the shape of the lamp he's holding changes between shots. The shape you can see changes between the shot of Dale knocking him out and the next shot that shows a wide shot of the people in the room. The other mistake in the shot is when Dale drops the remaining part of the lamp. Despite dropping it from about chest height the remaining part doesn't break when it's dropped.
Answer: Jeffrey Boomhauer is a Texas Ranger as can be seen in the final episode at the end when he sets his wallet down, it flips open revealing a Texas Ranger badge.