Looks like a deep stamp to me, buckstix. The top "circle" if an '8', would/should be the same diameter as the bottom one, it isn't - it is smaller.
If enlarged, ctrl button and + several times, is obviously a 6 - not an 8. The top barrel (right) is the one looking more like an 8, with a smaller top circle, however, when expanded to maximum, I see a small gap where the end of the top "tail" of the number 6 stops & doesn't quite meet the rounded bottom circle.