Your lender is going to require a higher down when no association or they won't even consider financing depending on who you're using. I'm glad you asked the question first though. It's a critical one.
It is hard to know with these smaller buildings but if there is a professional management company running the HOA, a placard would be displayed on the outside of the building with the company info. A unit sold last year in the building and the listing said that there was not an association at the time of that sale.