Thanks for the info. I should have the rifle in hand tomorrow and will check. Do you know what time period these were available?

They are still available from BROWNELLS under the name Billingsley & Brownell, described as Lenard Brownell bolt knob.
Please note that there is no relationship between supplier BROWNELLS and gunsmith Lenard Brownell.
https://americansocietyofarmscollectors....-Custom-Gun.pdf

DORLEAC
www.dorleac-dorleac.com