True, indeed experimentally from the mid nineteenth century though specialised equipment such as triple colour projectors and special screen viewers was needed to view it. It seems that the first commercially successful method of colour photography was the product Lumiere Autochrome in 1907, which could be printed but was still very expensive compared to Black and White.
As I said, the 1904 catalogue will have been tinted; but it does seem to be high quality photography of real coins, rather than of plaster-casts or line drawings more usually seen in publications at that time (when illustrated at all) and is exactly the sort of material needed to confirm provenance. Would I pay more for a well provenanced coin? I would still buy the coin rather than the name, but might go 10% higher than without.
Jerry