Welcome Ellen
Here is a good guide to what we need
https://www.shotgunworld.com/threads/please-read-before-posting-help-us-i-d-your-shotgun.423424/
and here, with Tolley information
https://www.shotgunworld.com/threads/j-w-tolley-sidelock.538103/

If you would like to send me full size high resolution close up images (a cell phone camera works OK) as attachments (not embedded in the email) to drewhausemd@yahoo.com I'll see if I can help.