Was Shuowen Jiezi 說文解字 originally written in the seal script 小篆? Modern editions of Shuowen Jiezi 說文解字 use seal characters 小篆 only in the headwords. This is also the case with editions published a few hundred years ago. Was the whole original 121 edition of Shuowen written in seal characters, or was the main text written in the clerical script 隸書?
Baidu Baike says "《说文解字》是首部按部首编排的汉语字典。原书作于汉和帝永元十二年（100年）到安帝建光元年（121年），现已失传，传至今日的大多是宋朝版本，或是清朝的段玉裁注释本。原文以小篆书写，逐字解释字体来源．全书共分540个部首．收字9353个．另有“重文”（即异体字）1163个．共10516字。《说文解字》是科学文字学和文献语言学的奠基之作，在中国语言学史上有极其重要的地位。"

But I can't guarantee it is true.