We know that there are several crosses engraved close to bm002 and bm007. See this webpage on my website. They are older than the current bordermarkers and marked the border when there were not yet numbered markers. Close to bm002 there are two crosses engraved in the rocks but Robert Darrieumerlou recently found a third one on the rock 2 meters behind bm002.

He shows that third one on my compilation of the pictures of the Darrieu’s. But you can see this third cross far better on his own picture on this webpage. It seems so visible that one wonders how other searchers could miss it (but I didn’t find any of them).
And Robert found another unnumbered cross, between bm001 and 002 and the altitude of 245 meters: see this page