Is the listing agent a Realtor or just a licensed Real Estate Agent in the state of Oklahoma?
Things to Think about:
1. If the listing agent is a Realtor and a member of the local board but your agent is not a Realtor or a member of the local board, the listing agent will work with your agent but does not have to pay your agent any commissions.
2. If the listing agent is not a Realtor, he does not have to work with outside agents if he does not want to, it is his listing.
Side note: You can use your own Realtor, but unless your Realtor is willing to work for free, you will need to pay for their representation, if the listing agent is not a Realtor.
Best of Luck.