Yes they were, Roland. Are you postulating that contrails from aircraft with tail mounted engines behave fundamentally differently from others? I'd challenge you to tell those of, say, an MD80 and a 737 apart a minute after they'd passed.
That said, I feel the contrail debate is a red herring; my money is still on the (single engined)X47B for the much more basic reason that the planform looks like it. This isn't the 50's with dozens of exciting projects. Even if some new mega plane had somehow been funded and built in super-secrecy, would it reallly be cruising over Texas in broad daylight?