Very interesting question, and I have some experience regarding this problem. So far I found very little variation in the data pattern of sEMG signal person to person. The data we find from sEMG signal is not critical in nature. Due to this, you can easily claim it as person dependent. One more thin I should add, sometimes the classification accuracy can be slightly varied person to person. If you need more help, you are welcome brother....
sEMG is subject dependent because each individual is different (muscle diameter, etc). Even placing the electrodes in the exact same place, on the same subject, in order to get the same signal as a previous session is complicated. Creating a general set of sensor positions for a myoelectric prosthesis is known to be a challenge in this area, thus the need to re-train your model (re-calibrate the prosthesis) each time the device is placed on the user.