Is my Tmobile dash unlocked? And will it work with tracfone?

I got a "unlocked" tmobile dash off of ebay, but I think its locked. I tried the tracfone sim and a Sprint sim card and it just says *searching* like it cant find a signal. Under the sim app there is an unlock link which gives numbers and asks for a unlock code.

Thanks for the info. What if i went to the store, bought a tmobile prepaid phone, and switched the sim card? Would I be able to use this phone for tmobile's prepaid service?