[Rules] Are Dug-in units considered to be in limiting terrain

[G. K. Zhukov]

Pretty much what is asked in subject line. Are dug-in units considered to be unspotted until they fire, an enemy unit closes to within 3 hexes, etc?

Thanks a lot in advance, gentle folk.

[vince hughes]

Only if they are in limiting terrain.

If dug-in in the open, normal rules apply

[G. K. Zhukov]

Only if they are in limiting terrain.

If dug-in in the open, normal rules apply

I kind of figured it out, as no mention of limiting terrain is made under the Dug-In rules, but somehow my (un)common sense told me otherwise.

Thank you.