It is very difficult to draw a conclusion, based on Internet photos only. I think it is likely an anomaly (non-"textbook") example. The parts appear to be original and fit together well. I would not be overly concerned about the crossguard markings. The blade is the thing, here. I don't own an Eickhorn SA Rohm, so cannot offer much of a comparison. Based on the photos, it looks like the etching differences may be no more than template differences and the amount of time the etch acid was left on the blade. You might consider sending photos to Wittmann, Johnson or another long-time dealer or collector for an opinion. In any case, I would not buy the dagger unless I was totally satisfied it is authentic. If you don't do that, the dagger will be of concern to you for as long as you own it.
