Thanks for the additional information! You are correct about the text of the crest marking on the receiver. It's very interesting to me that it could be a transitional piece. Being a B serial block does make it an earlier rifle, so now it's got me wondering if there was a serial cutoff point when they ran out of the older marked receivers or if they were assembled in such a way that the serial numbers don't necessarily dictate what parts a particular example was assembled from.

More photos to come this evening.