Welcome to the Gulf Stream Owners RV Forum!
I don't know what model you are asking about by the number. It would probably help myself and others if you listed the model name, such as SunVoyager, Yellowstone, Freindship, etc. so we could identify it.
But in all truthfulness, I don't believe there are any certain problems with any Gulf Stream coach line.
Usually used motorhomes sell on their own merits by the care and condition they are in. Just check it out carefully and be sure that all the components are in good working condition including the engine, transmission, appliances, hot water tank, and water system. Check carefully for signs of any water leaks from the roof, ceiling and inside cabinets.
If you do reply with the model name, maybe one of our members that have that model will respond.