I don't have too much experience with this type of Hereke. The market has changed a great deal since I handled them but from what I have seen this is my opinion
Assuming the size above is excluding fringe, and given the rug is in perfect condition with no wear, stains, etc and going by previous pictures on the other thread.
I believe age would be late 70's maybe 80s+. I don't think it's newer than 20 years. Value for a rug of this design for retail maybe $1200 showroom some maybe more, some maybe less.
Replacement for insurance maybe $2K. With these rugs the handle, structure, sheer, have a lot to do with the value. It's a very sweet little rug, a charming piece. It's important to remember colors and design may not appeal to everyone. However, purchasing for $600 is a good deal provided all else equal. Also, it is entirely possible if this rug was purchased overseas back in the 80's that someone could have paid several thousand for it.