I believe it should work. The fact that he indicates the cover has been off of it bothers me a little. On the upside, it could have an aftermarket chip in it, but on the downside, it could have been opened up for a solder repair job & was sold because it had intermittent problems. $50 is a good price but I would ask the seller to let you return it for a full refund if it turns out to be defective.
Vines has lots of these & puts them on ebay all the time. $40 used to be their starting bid price. Call & see what they want for one outright.