SB front bead needed
 

I can't tell if this missing front bead is press fit or threaded. This one is SN#177### so it's an early one. Any input from those in the know would be welcomed. Press fit or threaded?

I believe they were threaded and Conn.shotgun should have them

No threads are involved. You’re looking at the ferrule from a Lyman or Marbles taper-fit sight. The ferrule must be removed to press in a replacement sight. Replacements are available from Brownells, Midway, etc but the bead is made of off-white polymer and doesn't have the look of real ivory. If your SB is original you're better of trying to find a genuine ivory replacement. Be sure to get the taper reamer too (usually comes with the sight) because there's some variation in sizing of the ferrules and you don’t want to have the new bead to sit high on the rib.

You may want to reach out to Breck Gorman.

BTW, I usually remove the front bead. Just gets in the way.