18-Jan-2001 -- It appears that I am the second visitor to this point... Didn't get there first.
When I was there I used a Garmin GPSCOM190 and had an accuracy that day of 13 feet.
For me, 48N 12E wasn't at the marker rock but nearby in the farmer's field. I guess they didn't want a rock in the middle of a cultivated field. I stood in 3 inches of mud!
In fact in the picture I've sent, you see my car parked by the rock.
I've included a close-up picture of the plaque on the marker rock.