Importance of the rear cam sprocket key?

[jbg]

Hello,

I'm in the midst of replacing a leaking rear camshaft oil seal and when I removed the rear sprocket I realized the key was missing from its bore. I've looked back there, used a magnet, etc, but I cannot locate it. This lead my to ponder whether the key was there to begin with?

I've read that the key is there to align the sprocket in the correct position on the camshaft, its not there to aide in torquing the bolt that holds it. So, what does the collective think?

I'm sure I could use a piece of steel stock for a replacement to help align, but otherwise is it really needed?

Thank you.

-Jim