Back cover needed for 56 philco table model

[Tubejunke]

This set is a 21" and the model # is either 4136 or 4138 according to a sales brochure that I looked at. As I no longer have the cover (lost back in 1986), I don't have a specific model # to go by. Heck, working without a cover for all these years may be at least one reason that it has never needed restoration, but it has been such a good one I would like to see it complete again.

Thanks