I'm with Rod. If the pump is still pumping, flush it out yourself like he talked about. If you're afraid of plugging the injectors due to any trash loosening up inside the pump during your flush, merely crank the engine for about 30 seconds with the injection lines completely disconnected from the pump.
I'd save the money and do it myself. I can promise you this much: for $300, you're not getting a rebuild of that pump.