I sure wish you'd asked first....
Well intentioned "Restoration" has ruined the value of many an old firearm and oft the fun factor also.
An acquaintance back in the 60s had his ancestral C&B Colt redone by Bubba and Sons. Not only the value was reduced by 75%, it wasn't the way it was when his ancestor took it off after Lee surrendered. As he aged, he regretted hs actions deeply.
Most collectors will tell you they'd rather see a bit of rust than shiny new metal surfaces, not matter how well done. However, condition determines value 90% of the time.
As for the piece in question, chances are it was duffle bagged back from Europe around 1945.
It's almost certain to be chambered for 2 1/2" shells, not the more modern 2 3/4" 16 gauge stuff we shoot now. Chokes are overly tight as a rule also.
The 6.5mm barrel could be for the Mannlicher, Mauser, Italian, or other 6.5 cartridge, many which are not currently stocked at your local gun shop, much less Wally World.
Upside, almost ALL Drillings( The word comes from the German word for three) are well made, high end guns and quite functional IF you can find ammo and if the last 80 years or so have been kind.
Parts? Heck, no. Many makers worked in small shops and filed/forged out parts as needed.
Worth $125? Certainly.
Worth $1250? Possibly.
Worth getting to a qualified smith for a lookover?
Absolutely.
HTH....