A/C compressor-to-conderser hose seal????

[Kneale Brownson]

Is there supposed to be an O-ring where the hose from the A/C compressor to
the condenser attaches to the compressor?  I've had that hose bagged up
while I've been replacing the compressor and I went to attach that hose and
don't see a seal in the bag or anywhere else nearby (like if fell off an
rolled somewhere).   The fitting on the hose has a shoulder that a nut
presses against a fitting on the compressor.