Washing and styling does make a difference
sometimes there is oil on the nylon that makes it feel flat and dull.
With nirvana ponies, such as the Greeks, you will never get a 100% match in either texture or colour. Each country used its own hair, which is often very different to Hong Kong/China hair.
Something else to take into account us new vs. old. Vintage ponies have vintage hair
Time, play and anything the pony was exposed to will change the nylon so it will be different to new hair.
I hope this helps!
Love pkw xxx