@SpeedRoopreviously asked about the Kanri number on the dashboard at the spot where there would normally be a pen holder. It's surmised that this was most likely placed there by a previous owner, as it is not a factory inclusion that appears in any period photos. @HS30-H had clued me into the fact that these rally pen holders were actually still readily available, so I bought several of them with the thought that I'd have to retrofit one with some sort of mount, in order to properly affix it to the dashboard. In stock form, they appear to be designed as clip-ons for a clipboard, or other hard, thin surface. With some samples of the pen holder in-hand, I elected to take a chance and finally remove the Kanri badge, and hopefully re-fashion a new pen holder and custom mount to be placed in the same location.
I had always suspected that the Kanri badge was simply a decoration that covered up some form of glue blemish or tear left by the original holder when the car was converted to street use. However, I was happy to be mistaken - after a little careful prying, the badge came off, revealing a precise 1/2" slit and groove that had been cut into the dashboard. The groove fit the new pen holder snugly, so after a little massaging, I managed to situate the new pen holder pretty much as it appeared in period photos. Job done!