Change out 300D injectors

[Barrelhouse]

They tell me that my injectors are leaking badly enough to warrant replacement. The shop that has the car now doesn't do diesels and believes that there is something complicated about changing the injectors out. A friend with a 300D says that he did it himself and that putting one in was simply the reverse of taking one out except that you change the little hoses and O rings out. Has anyone out in diesel land ever changed injectors? This engine is a rebuilt(in 95) early '77 if that makes any difference. Sitting for several months is said to have caused the leaking even though some of them had been seeping a little for years. Thanks