If Dish carries the "main" channel, in theory they will provide guide data for the sub-channels. When they don't, it's because of an "error", somewhere. It could be that Tribune doesn't know about the channel, Dish and/or Tribune have incorrect data, the station changed the TSID by mistake or on purpose and in turn didn't notify Dish/Tribune.
Now, if Dish doesn't carry the local at all, ie a low-power local, you will NOT get guide data (period). Check switch, channel scan, etc all you want, it wont make a difference.
As an example, I get ABC, CBS, NBC, FOX, CW, PBS via Dish. With my antenna into my Dish receiver, I get all of those plus a TBN affiliate. I get guide data for those, including their sub-channels (1). For the TBN, it lists "Digital Service" in the guide.
(1) The ABC affiliate added "Cool TV" months ago that is still unlisted; one of the PBS sub-channels is incorrect. See first paragraph for why.