yes, those rubber seals can be replaced. do a search for "olives" here on the forum. They can be hard to get out of the hardline though.... I burned mine out with a torch, and picked out crusty remnants.
That said, if you are getting fuel at an injector, you should be close to getting it started. I wouldn't mess with fuel olives until you verify it runs, unless it is a real gusher. Have you tried cracking all the injectors and cranking until fuel comes out of each of them? With mine, I can normally get it bled enough to start just by cracking 4 injectors, crank till fuel, re-tighten, crank and.... vroom!