Seller requiring proof of funds and offer

[Account Closed]

Hello everyone! My husband and I are new investors and are currently looking for our first property. I found a triplex that cash flows, however the seller is requiring proof of funds and that an offer be made before they will allow us to go inside the occupied units. Is this typical or should I consider this a red flag? The property does need some work, but is livable, and the unoccupied unit is currently being renovated.

Thanks for your help!