Bills are Made to be Broken - S4-E3
Continuity mistake: Whilst Bill is practising football in Hank's yard there is an aerial shot that shows Bobby & Hank walking towards Dale & Boomhauer and are close to them. In the following shot they are quite a bit further away from their previous position. Also the position of Dale & Boomhauer next to the garage changes between shots.
Bills are Made to be Broken - S4-E3
Continuity mistake: When Hank and Bill are sitting on the hood of Bill's car and talking, one shot of the football field shows it to only be about 70 yards long between the end zones.
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.