To all that replied, thanks for the inputs!
Since my first post, I've contacted several of the suggested gunsmiths and the Merkel factory service center.
The master at the service center was very informative and his estimate for the repair surprisingly reasonable... I decided to hang on the the gun!
In the mean time, I ginned up a brass shim to bring the gun on face to get through the season... it worked well, and I got to enjoy the gun for the entire season... what a hoot.
Now, I'm considering working on the chokes... it's really tough in the pines shooting quail with F/IF chokes though I get solid hits/misses in the open fields. I don't know if Briley does 16 gage, but Teague seems to be the best of the best regardless of choke.