As usual, there is nothing particularly clear here. But I thought I'd post what I have learned for others' "benefit."
There seem to be several different Bosch part numbers at least loosely associated with our FPS.
On my rail, it is Bosch part #0281002534. This is still available, but has been superseded by 921. I can't help but wonder if it was superseded because others besides me had mysterious sensor failures when the rail was removed from the engine.
As you start to look at applications, you find that the 534 part number was used at one point by the Cummins 5.9L and the Duramax 6.6L engines. For the Cummins engine, you now find that the part listed is available with an 851 suffix. Some places also list that for the Duramax. Others list still another part number. Prices vary greatly, including for the same part number but according to which application you use. Generally speaking, the Duramax Bosch part comes up being cheaper, but is not guaranteed to be the 921 part or the 534, either of which should work for sure.
One other person on LOST reported that they found a part with a 706 suffix, installed it, and it "ran great." Don't know for how long, but... All of these list as 1800 bar sensors, have the right terminations and supply voltages. I don't know how they vary from one another.
Then there is an Airtex part, supposedly made in the U.S. by Airtex, listed for use on our engine and sold by Rock Auto. Their part number is 5S7054, and is the least expensive option, and comes with a 12mo/12kMile warranty. (EDIT: this is the part I ordered, and it is actually the Bosch 534 part. No sealant was needed, and no fuel leaked from the rail when removed.)
I have no idea whether a sealant of any kind is recommended for the threads. At 20+kPSI, it sure seems like a good idea.
That's what I know.