Yes, but just because a ticket is available for cash doesn't mean its available as an award. It may not even be able to VN or GA's members, but they then have to release inventory to DL on those flights in award classes for DL to be able to book.

If you see the flights available individually when you search as an award, then call and ask them to manually put it together, as there may not be an award fare with the routing you want filed. Sometimes when they manually do it, they have to add the second/last flight first to confirm and work backwards from there, FYI.