Looks like a Sauer action to me as well, Chief.
Course that it not unusual as most guns built by small shops were from Sauer actions. Lindner included.
It may be very difficult to replace the trigger guard with something fabricated of metal. I might simply use acrylics to do a good repair on the present one.
Nice gun and Dave is in the ball park as far as price goes.
Best,
John

Humble member of the League of Extraodinary Gentlemen (LEG). Joined 14 March, 2006. Member #1.