Although Cook and Wedderburn describe no. 39 in the Reference Series as filled by a Burgess enlargement after Holbein (catalogued here as no. 39bis), the passage from Ruskin's catalogue which they reproduce in their main text lists the frame as blank (to be filled with work by Holbein).
Ruskin, John, Catalogue of Examples Arranged for Elementary Study in the University Galleries (Oxford: Clarendon Press, 1870), cat. Standard no. 39-040
Ruskin, John, Catalogue of the Reference Series Including Temporarily the First Section of the Standard Series (London: Smith, Elder, [1872]), cat. Standard no. 39-040
Ruskin, John, ‘The Ruskin Art Collection at Oxford: Catalogues, Notes and Instructions’, Edward T. Cook and Alexander Wedderburn, eds, The Works of John Ruskin: Library Edition, 39 (London: George Allen, 1903-1912), 21, cat. Standard no. 39