How to find out if UJT 2N2646 is original or not?

I bought two UJT (2N2646) before yesterday. I tried to make an oscillator but it was not working. There was a guy from FB who said it could be a duplicate (not original) one. It must be tested. How should I test if it works or not. I googled some and found about diode and resister testing. But those articles were so distorted that I couldn't understand. Could you please help me uunderstand (or teach me) how to test an UJT(2N2646 or any other) with multimeter?

Did you read this article? Knowing the construction of a UJT should help in testing one with an Ohmmeter.