If I put the cursor on the left side of "作", and type C-u C-x =, it gives:

--8<---------------cut here---------------start------------->8---
        character: × (215, #o327, #xd7)
preferred charset: chinese-gb2312 (GB2312 Chinese simplified: ISO-IR-58)
       code point: 0x2141
           syntax: _ 	which means: symbol
         category: c:Chinese h:Korean j:Japanese l:Latin
      buffer code: #xC3 #x97
        file code: #xA1 #xC1 (encoded by coding system chinese-iso-8bit-unix)
          display: by this font (glyph code)
     -outline-Courier New-normal-r-normal-normal-13-97-96-96-c-*-iso8859-1 (#xD7)

Character code properties are not shown: customize what to show

There are text properties here:
  auto-composed        t
  fontified            t
--8<---------------cut here---------------end--------------->8---

and put the cursor on the right side of "作", and type C-u C-x =, it gives:

--8<---------------cut here---------------start------------->8---
        character: ÷ (247, #o367, #xf7)
preferred charset: chinese-gb2312 (GB2312 Chinese simplified: ISO-IR-58)
       code point: 0x2142
           syntax: _ 	which means: symbol
         category: c:Chinese h:Korean j:Japanese l:Latin
      buffer code: #xC3 #xB7
        file code: #xA1 #xC2 (encoded by coding system chinese-iso-8bit-unix)
          display: by this font (glyph code)
     -outline-Courier New-normal-r-normal-normal-13-97-96-96-c-*-iso8859-1 (#xF7)

Character code properties are not shown: customize what to show

There are text properties here:
  auto-composed        t
  fontified            t
--8<---------------cut here---------------end--------------->8---

> By the way, I think it's not coincident that GB2312 code for
> "作" is "\xd7\xf7".
>
> (decode-coding-string "\xd7\xf7" 'gb2312) => "作"

Oh, may be that why "作" is displayed there.