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Unsure where you got 1977 from. The serial number places it in the very early 1990s, likely 1990. This may be a rifle made for a Remington employee. First one I've seen marked so. This is either the assembler or inspector.
The woox reference guide I believe is AI produced junk. Run away from it and never look at it again. Its totally wrong on most aspects. The rifle you refer to is unique for one reason or another. Custom shop guns are NOT date coded. Employees could inspire how the end product looked. I wouldn't discount a 90s rifle if you like it. It would still be considered desirable by most.
Some info is that Remington stopped date codes on 8/9/99, this was unpopular with the public and Remington started date code stamping again on 10/1/01.
I held this rifle recently. The bolt release worked fine. However, when re-inserting the bolt it would slide back out. If you dry fired the rifle the bolt would then lock in place.
Does this mean the rifle had a trigger job? My other M700 bolt release did not function like this.
Not necessarily a trigger job. I would check for a Sear Pin that is protruding too far and binding against the Bolt Stop, just enough to bind and just enough that dry firing will dislodge and set things right.