some schools ask you in the secondary application if you have applied to any other professional schools but I don't think they ever asked if you took the OAT or other tests as well as DAT.
Most people on SDN will not be 100% sure what the adcoms will ask, because, quite frankly, most of us are not adcoms. However, just to be safe, I would prepare in advance to answer the following question: "So I've seen you've taken the OAT... why was that?" Better safe than sorry...
You're supposed to list any other standardized test you have taken, at least from what i've heard. I agree above, pick one and put your all into it. Good luck.