This article is documentation of a capacity test of 5 x Hobbyking 2500mAh 18650 LiIon cells (9210000181-0).
The cells were purchased on 26/02/2018 (~$7 + shipping) and received at about 30% charge. They were each charged in a XTAR VC2 Plus charger at 0.5A until charged.
The cells are 65mm long, and do not claim to contain protection modules which are prudent in some applications.
Each cell was then discharged at 1A (0.4C) to 2.8V, the discharge was captured.
Above are the five discharge curves. All cells gave more than 2400mAh capacity, and the cells were very consistent.
Specified discharge cutoff is 2.5V which would take all of these above the specified 2500mAh, but that is a rather low discharge voltage that you might not want to use. The discharge curves show that very little additional capacity is obtained by discharging below 3.0V.
Are they compliant with the specification? Well that depends on criteria for the test, charger, temperature, and battery history. It is not uncommon for the second and third discharge to be a little higher in capacity.
To my mind, these are very acceptable results at this point. I have tested low cost Chinese 18650 which had less than 20% of the labelled capacity