Welcome to the Forum!
As Chet15 has mentioned above,, they are desirable in that model & length. But the BIGGEST thing is the condition. The Bicentennials only bring a premium over regular guns if in the condition you seem to have. As to value,, as noted there used to be a number of "Liberty" collectors, but they do seem to be fewer nowadays. But as most of us collectors like such things,, a price for yours would most likely be in the $50-$100 over a similar model not marked with the Liberty statement. Most Liberty guns only bring an average premium of about $50 to $75 but yours is a bit more desirable in that model,, and you have the shipper. It all adds a little to the package.