Do I need to receive an estoppel letter?

[Konrad R.]

I'm closing on a property next week. There is a tenant in place. Do I need to get an estoppel letter? Does the seller furnish the letter? I have already received a copy of the lease. There is a discrepancy with the security deposit. The written lease shows zero security deposit, but I was informed by the tenant that she put a $500 security deposit with the original lease. I have the second year of the lease, so the $500 may be listed for the first year and not transferred over (tenant has lived there two years).