You're best off replacing all of the o-rings on that bank if you're going to be disturbing the rail at all anyway. If the pintle caps look alright, you could probably leave them alone.
Ya I would do em all while its apart...thats a pretty tit job as long as you lube it up good.. I double check my fit on all the injectors once in the rail...any bind and it could be a leak...pull it out and re-seat it.. been there and had that...was not impressed...
The rubbers are tit...changing the pintles blows !!! those mofo's are a pain.