Are questions about identification of specific ancient cylinder seals on-topic?
Yes and No. It would depend upon the way the question is put.
If you simply ask something like What do these seals represent? then there is no obvious connnection to mythology. The question is likely to be closed for being off-topic or for being unclear.
If you ask something like Are these seals representative of the myth of ...? then that should be on-topic. Especially if there is wording in the question's body showing why you think they might be representative.
Like all SE sites, the trick is in creating good quality questions.