Coop is requesting money to review their bylaws

Hello! I submitted an offer for a coop apt and got accepted. My offer was contingent upon satisfactory review of the coop related documentation (financials, by-laws, etc.) because they wouldn't show it prior to receiving my offer. Now, as the offer is accepted, my agent said they request $50 for each document and they only have financials for 2017. Is it a normal practice for coops in New York to request money from a prospect buyer to review their bylaws and financials, and don't even have a complete document package? Or should I treat it as a red flag and walk away?