Sapper school for non 12B?

I've never heard of a 12M going but there's no reason they can't. But then again when your MOS is 100+ people big there's a first time for everything. 11Bs can and do go, but it's a lot less common because most units want them to be Ranger qualified before they're willing to send them to Sapper school

In theory, yes. The trick is finding both an open slot and a unit willing to send you. Most 11B units see no need for a Sapper tabbed team leader or even squad leader. They have to justify spending the money, which is hard to do for a standard line unit.

Dapper School is now open to all MOS's within the rank restrictions, BUT priority goes to 12b, 11b, 19d and SF engineers, then everyone else.