A survey is useful to determine your exact property boundaries, and costs for the survey can be negotiated to be paid for by the seller, buyer, or split between both. Generally, the person disputing the boundary will pay costs unless the other person has some sort of incentive for paying for the survey.
You will want to be sure that the legal description in the deed is accurate as it is a material term that describes the subject of the contract, the property. An error in the legal description can negate the entire transfer and cause significant transfer issues as a result. You should make sure that all the information in the transfer documents is accurate, and you'd be wise to consult with an attorney to draft these documents.
It might be a good idea to get extended tilte insurqance which insures the validity of the legal description. The seller has an interest in providing avlid legal because the wrranty deed that is usually provided by the seller includes a warranty of good title. The errant legal is potetially problematic for the seller. So be sure to informe the seller of the problem.
I agree with both previous answers and I would reccomend putting notice in to the agents and the closing agent that you have an issue now rather than later.
Only If and until you and I sign an Agreement for Legal Services, I am not your attorney. These answers are provided for informational and/or novelty purposes