OK... I pulled my SKB case out of the closet... not as difficult as I thought it might be (it was only two layers back). It appears to be the case in the ad posted, but I didn't see a model number on the case, so can't be 100% certain.
So, my Guild D-55 DOES fit, but...
...it isn't a nice snug fit around the body of the guitar. In fact, it's quite loose... looser than I prefer. When snugged up against one side, there as 1/2" - 3/4" of space on the other side. The body length of the case is a bit long, as well. This is consistent with the dimensions in the ad... the case is 16.5" across the lower bout, while a Guild dread is ~16". You would definitely need to stuff some old towels or T-shirts (plural) if you want a nice snug fit.
I had forgotten... since I haven't had that case out of the closet in more than 2 years. The last few times I have traveled with my 46 or 55 (by car), I have used an arch top TKL case that fits either dread like a glove. I picked that case up in Exc used condition from a local shop for $65.