A characteristic of most box lock guns, like the American mfg. Parker and AH Fox (amongst others) is the sear axle pin at lower rear section of the receiver does hold the stock in place against the receiver- That is why you need to let the hammers down (you'll see the firing pin tips protruding from the receiver face) after you have done this, to release the coil spring tension against the cocking toes of the hammers- Once you have driven out this pin with a properly fitted drift punch, you can removed the sears, which, like the hammers, are made "opposite hand" .
Austin Hogan, our PP editor, and others, place removed screws and other parts on paper marked for the order in which they were removed-when you re-assemble your VH 12 bore, just reverse that order--
Production line shotguns, even my favorite- the legendary Winchester M12- had more flexibility for pins and machine screw interchangability- but all the fine Parkers were hand fitted, and keeping such items in proper order is important--
Looks to me from your fotos that oil soaking may have caused the head of the stock to pull away from the receiver and the top tang- All the minor issues you detailed here can be repaired by any competent double gunsmith, and you will have a shootable fine 12 Parker as the end result. You are way far better off with a Parker than had the gun been a Savage/Stevens double--they are the Rosanna Barr's of the double gun world, Parkers are the Martina McBride of same- Happy Holidays
