I've only seen kegs with removable poppets. Like Yooper said, if they weren't it could present problems. Sometime they need torn down and cleaned thoroughly.
New kegs are a waste of dinero in my opinion. Yesterday somebody put a thread about $30 5g ball lock cornies. These are used but for 110 you can probably get three with shipping. http://www.kegglebrewing.com/view_cart.asp