Once they get any miles on them, seen as little as $20 or $25 bucks each asked for them.
I bought a spare set of phenolic blocks on Evil Bay as "what the heck" spares for $100 or so - came with a set of those early RoW injectors, and 50% of them tested good after cleaning.
So it really depends how fast you want to sell 'em. I don't think you'll see much interest in selling more than singles @ $100 each, but folks will jump all over a good used set for $250.
I've got a bunch of spares (and a working set in the motor) - but even I would probably go $500 for a set of six (almost) new, genuine Bosch. Let me know