A retirement extension of stay is pretty much just a couple of dates (date of approval and a Permitted to Stay Up to date), a short sentence(s) under each date, a hand written extension number, and in upper case letters the word retirement.

I have my original non-imm O visa plus 8 extensions in my passport and only on one has the officer hand written "retirement" underneath it.

Yes, some immigration offices don't have fancy stamps and indication of the reason for the extension seems to be optional, as it is not always done.

Flame removed.