Non-inverting amplifier with variable gain from 1 to 15
Yes, it means the open loop gain is 40dB, i.e. ~100 V/V (20 log 100 = 40 dB), up to around 300kHz. It is a typical open loop gain of differential signal.

Since you want to amplify the input signal by a factor of 1 to 15 and the output signal is:

out = in * (1 + RV1/R1)


you have to make sure RV1 will vary from 0 to 14 * R1 = 14 * 3.48 = 48.72 Ohm, so 50 kOhm resistor will work.

Of course you cannot get more than Vcc on the output, the opamp will saturate. Therefore for your maximum amplification of 15, when RV1 = 14R1, your maximum input signal for linear amplification may be Vcc / 15, this will be then amplified to the value of Vcc. All the input voltages above Vcc / 15 will result in output of Vcc. In general, for any amplification factor of G the maximum input signal for linear amplification is Vcc / G, and opamp will saturate for voltages above that.