On this coin would the following be considered a signature variation. This is both images are from 1905 coin. In one of the images the A sits lower compared to the rest of the signature. Both may be the “Signature without dot” variety but also may be too worn to tell.
Belgium coins are well known for the varities.. If you want you can find several per date..
I only keep the “overdates” and bigger varieties.. On my desktop the photo is good enough to see all 3 varities i have from 1905. Hope it will be visible also on mobile devices..
Top left: the M is looking like an “N” Top right is normal one. Bottom one is repunched “M”
Worldcoin collector by date & variety.. (Always on the search for Doubled dies)