Also it might shed some light this link about Japanese calligraphy (shodou). It shows the three main calligraphic styles, but there two more that are not shown there (here are cited but not shown) and I think the one used in the buckle is reisho.
As everybody said before, there are just different styles of writing, like fonts. Also kanji were not invented anew in 1946: some were simplified, but not many, and some were considered not of daily use, which is what jouyou kanji means.
Do you have a translation question?