Price = $260 + $25 = $285.
BV3 for Marson, OQ8 for equivalent of a unengraved and plain stock BLNE. BV3-OQ8-CC7 (Shootable but needs expensive repairs or restored with stock and barrels replaced) = $300.
The highest possible value would be BV3-OQ7 (equal to a 1/3 engraved BLNE)-CC4 (Heavy use, but no abuse or remanufactured) = $1,200.
I'm going to say it is a bit of a bargain, but caution you to not spend much money on it due to the limited upside potential. It left the Marson shop as a solid, servicable arm with minimal extras and little enbelishment. Likely, you can get a lot of good, fun shooting with it and learn a lot.
DDA