Leaking from carb fuel filter

[kcackler]

So I changed the fuel filter the other day in my brother's 86 GMC Sierra with a 350 and a 4 barrel carb. Ever since then, it's got a pretty good leak coming from the fuel filter connection (The big connection that goes to the carb, not the small connection that goes to the big connection)

Did I lose a rubber washer or something when I took it all apart? I've verified that it's screwed on straight and that it is screwed on tight, but it's still leaking around the threads. Not sure what to do next, since I'm not sure what the problem is.

Do the auto parts stores sell the metal piece that the fuel filter sits in and connects to the carb?

Thanks in advance...