I guess I have been lucky. A gunsmith opened the chokes on my 20 gauge about 30 years ago and he might ahve glassed the inletting. I don't remember and am afraid to take off the lockplates to check.
He appeared to be knowledgeable on LC Smiths and warned about the stocks splitting at the head so he might have done the glass bedding.
The 20 gauge was about 90% when I bought it and didn't need much work. the 12 gauge Marlin era needed to be rust blued. It is likely he glass bedded that one.