hi jsquared,
these are somewhat more uncommon, but not exactly rare or not allowed to be imported from my understanding. most of these ive seen were made in the 80's, staining is going to affect value a lot. If it is silk (some brought in were not real silk) brand new in unused condition
at retail, i have seen these recently at around $4,000 in 9x12'. Real silk ones were expensive, but not too many people go after these much more.
We really have to see more photos of the stains to say for sure, but in case you can't get them, for this type of rug, even with mild scattered stains, automatically subtract (from the $40 per foot example above) 40%-70%, given it's private party sale, subtract another 40-60%
the market is soft, I would suggest trying craigslist. I would recommend second opinion too