Both classes of St Charles boxcars of 1897 and 1899, as well as the C&S built 1907 ASF (Phase 1) boxcars all had wood board roofs, with an interior metal roof to prevent water leaking in from above. The D&RG 3000 series boxcars as built in 1903 had the same feature.
While I understand how they were constructed, from Derrell Poole's and other's plans, I've never actually seen a photo of one. Cause, well, they were hidden.
But in searching for some of Pat Student's C&S boxcars on the D&RG, as interchange cars, I spent a lot of time studying this fascinating photo of the Salida yards, c1920, with the RIP track in the foreground:
D&RG boxcar 3115 is having its roof repaired. All the wooden exterior boards have been removed and all that is visible from above is the interior metal roof and the car rafters. Looks like new carlines are being fitted prior to re-roofing. And is that a new side door I see, all raw wood?
And further to the north, on the same track, another 3000 series boxcar has new roofing boards cut and ready to be nailed in place on the roof, the interior metal roof also visible.
And just behind it is another D&RG 700 series drop bottom gon. Do you think it's just returned from Breckenridge, via Leadville?
Speaking of metal roofs, lurking in the right corner of the Salida yards is a 4000 series D&RG 30 foot boxcar with an outside metal roof and lateral roof walks.
The many 3000 series boxcars on adjacent tracks won't obtain metal roofs until their 1924-1926 rebuild, but curiously 4050 already has one. And it's not the typical D&RGW style metal roof, with the wide folded ribs at the panel seams. This one has what looks like a "narrow rib" outside metal roof, like on the C&S phase 2 boxcars of 1908 and the SUF cars of 1909-10. One can even see the cinders that have collected on the roof panel, between the ribs!