FWIW I remember these selling for $3500 brand new when they were making way for the APC replacement.
I bought a like new ECC for $3500. I ended up deciding I wanted the upcoming at time URX4 guns as they were lighter and more practical. I sold it I believe $4200
I got an APC M-Lok with MAMs but no sights off EE for $3300.
My point is, there definitely are better deals out there than full retail if you can be patient. For an EC, $3500 would be fair, but the market has fluctuated multiple times on SR-25s the last 5 years. It’s at a higher point again right now