Koetsu Silver Onyx? Low Output Moving Coil Cartridge

I have for sale a used Koetsu Silver Onyx? low output moving coil cartridge. I am uncertain the age, playing hours, the provenance of the cartridge, etc, however, when installed on the vintage AR-XB turntable and played through a modest moving coil phono pre-amp, the cartridge sounds good, if only a little more flat than any other moving coil cartridge that I have had the pleasure of listening to. However, from research that I have done, I am not surprised, as these cartridges seem to be finicky about capacitive and resistive loading and as well seem to have a high frequency roll off that may be a characteristic/hallmark of the brand. There is no obvious distortion which might indicate that stylus is worn beyond use. On close/magnified inspection, it does appear that someone may have used a stylus cleaning solution that may not have been compatible with the shrink-wrap used to contain the suspension or damping material surrounding the cantilever. I cannot discern if this is having any effect on the cartidge's operation as I haven't another Koetsu to compare it with! For reasons above, I am selling the cartridge as is. The cartridge will be well packed to ensure that it arrives intact. My understanding from Overture Audio, that a rebuild/replacement of this cartridge would cost somewhere in the neighborhood of $5K with trade, but a similar new cartridge would command $7,200. Please see pics for closeup of the cartridge body, cantilever and diamond stylus. I am conservatively rating 5/10 due to cosmetic condition only. Make offers.
Approximate Specifications:

Body: Onyx
Type: moving coil
Coil wiring: silver-plated copper
Magnet: platinum
Cantilever: boron
Output: .3mV
Frequency range: 20Hz-100kHz
Channel separation: 25dB/1kHz
Inner impedance: 5 ohms
Channel balance: .5dB/1kHz
Recommended impedance: 30 ohms
Weight: 12.5g
Compliance: 5x10-6cm/dyne at 100Hz
Recommended Tracking Force: 1.8-2.0g
Recommended Load: 80-1,000 Ohms