Technically your offer isn't even valid without a pre approval letter from a trusted bank. That letter lets the sellers know that you are financially able to purchase the property. In the case of a cash deal, a letter showing proof of funds is required. When I represent buyers I don't even start looking with them until we have that letter. When I represent sellers, I will not present until we have that pre qual letter. AT the end of the day, it helps you as a consumer to go out and get one. That way you know where you stand. Banks have stricter lending requirements because of the housing crisis that we all lived through.
I'd advise to go out and get that letter.
Hope this helps
David Manzano JR
Hunt Real Estate ERa
Like me on Facebook.com/ManzanoRealtors