Round table

Of course, it's possible. The Garrison of Order (GO) is placed after the castle, and its position between territories doesn't matter.

In general, the boundaries of zones for different types of territories are determined precisely by the transition between the type of land; the guard tower can be located even a kilometer away. Sometimes, in Jeb, it generates a situation where the central castle can be captured without breaking the Garrison of Order.

If a Barbarian land is generated when entering the castle, then it's possible.

But what if it's a desert? Does that immediately result in a tech loss?