I have always wanted one of those. Okay, looking at the schematic in the '67 Shooter's Bible, unload the gun. Have you tried removing the bolt while holding the trigger back? How about while pushing the trigger forward? I've even seen guns where the trigger hit the trigger guard before releasing the bolt. Try everything with the safety in different positions. Try it cocked and uncocked. You won't hurt anything if you take it easy and don't force anything.
I do not see a part listed for any kind of bolt release
Looking at the stock, the Takedown Screw (63-268) is in front of the trigger guard and then there's a Front Sight Nut (63-680) that goes on the Front Sight Screw (63-226) that goes into the bottom of band around the barrel that holds the front sight hood on. Does it show under the muzzle?
Have you taken the 2 trigger guard screws out yet? Did the trigger group come loose? I can't quite make out how the two screws fit.
It does not appear that the front swivel attaches to the barrel because the barrel they show is smooth on the bottom, but it's just an old half-page drawing.
How does it shoot?
I didn't know this model had a Barrel Lock Screw under the front of the receiver.