I concur with previous observations but have one additional note. The pictures show a puddle of grease on the flatbed, most drivers keep their stuff clean so I assume it is from your truck, the point of concern is that there should only be grease in your knuckle but if there is oil then that lends to an axle seal failure. If this is the case then yes you do have to do a rebuild because to get to the seal you have to tear into it.
I would watch OTRAAM on YouTube for his video, Ryan give a good breakdown of what would go into the repair and it will give you a good reference to know what to expect and the terminology a repair shop might throw at you when quoting for the job. The rebuild kit is fairly inexpensive but what will kill you is the labor.
If you choose to attempt the repair yourself, the rebuild might be less intrusive/costly if all the pats are within spec and all you need is the basic rebuild kit. IMHO I would call on of the vendors on here that are reputable and knowledgeable and can help out.
@cruiseroutfit are great to work with and ship fast, Kurt and his guys at Cruiseroutfitters are solid people. As previously stated, download the FSM here (resource section) for free and it will become your best friend.