It’s quite difficult to visually isolate one color layer from another well enough to make out whether they are printed from the same block, but it’s certainly plausible. With IR photography, it might be easier to separate the (presumably) carbon black layer and see the two impressions side by side. In my digital archive of decorated papers that don’t belong to me are two more examples of a very similar paper on bindings containing 1788 Bern and 1794 Stuttgart imprints, respectively. In these examples, it’s clear that the blue/purple impressions are a second fill design block, rather than a shifted impression of the black keyblock.
That being said, the keyblock design is printed in blue in the c. 1924 Rizzi sample book (#528), suggesting Remondini origins.