Question on a Browning BSS Shotgun

[Griff56]

I have a sweet little 20 Gauge Browning BSS that I shoot on occasion. I got a wild hair and decided that I would like to replace the front bead on it with a larger white bead.
The original is a small silver one.

My question is what kind of mounting system is used to hold the original in place. I ASSUME that it is screwed into
the rib. But then again we all know what ASSUME does for you. If it is screwed into place, I believe that they have a
special tool used to remove the bead. Now I wonder what size thread will be needed to replace it. It it is soldered on I guess I know what to do about that.

Thanks for your time and replies.

 

[moosehunt]

I don't recall for certain if it's threaded or pressed in, but "unscrewing" it will get it out either way. Then you'll know. If it's pressed, you get a replacement that presses in or tap the hole and proceed with a like threaded replacement. If it's threaded, then measure the thread pitch after you take it out and get a matching replacement.