Who would do that? The Fed (USCGS/NGS) started to realize that stamping elevations on disks was a bad idea in the 50s and 60s. Given the coordinates are fairly close in the Northing and way off in the Easting they are likely NAD27 meaning it may date back to when it was a standard practice. It may have been standard practice because it was the first time the country had a well accepted horizontal and vertical datum and the surveyors at the time thought the coordinates and elevations of a point were permanent and would never change once they were on a datum. Of course they never imagined readjustments every 7-10 years like we have on NAD83.