Generally Wizards of the cost only places Core Rule Books in thier SRDs, as everything else is considered an accessory. UA would be a major possibility of NEVER making it to the SRD as it is both an accessory and lacking of any offical rules whatsoever. It's a book of variant rules and it's not to be confused as a rules update.
Urban Arcana however is considered Core Rules because Urban Arcana was first introduced in the d20 Modern Core Rulebook, if they ever produce guides for Section 7 and Shadow Hunters, you can probably be safe to assume they'll be added.
A good way to check for something being added into the SRD, look for the word "Accessory" on the book cover, those typically do not make it in. I say typically, as two of those accessories were featured in the new DMG and thus made it into the SRD.