Welcome Matt, I have the diagram XD2S. As Rabin mentioned the EGR stuff is worthless to make work when most of the time it doesn't. The only thing for you to plug is the vacuum line source that supplies vacuum to the regulator atop of the injector pump. The EGR regulation originally worked to control the turbo waste gate during engine warmup. My current TD has this stuff functioning and I've had many that don't. I prefer without!
You have a good starting point with your 505, there isn't much to the diesel versions except simple maintenance. The number one issue with these is cooling, so keep this in mind that its doing the job or a warped head will cost you dearly.