While I have never seen one in person, and the most recent photograph of one I've seen was probably over 10 years old, it may indeed be what you suspect. Locality information on the photographed frog would of course be key here.
I am agreed with the orange. If the frog is CB it is possible the colors faded. The other thing is there is so much variation in other species in that region that it would be foolish not to almost espect it from this. The Iquitos region is huge, any more in depth information on it? I know Mark Pepper has been in Peru and is going back to that region, maybe he has a better idea. I'll hopefully make a side trip there when/if I go to Ecuador in the spring.
I've spent some time in the Iquitos region and am familiar with duellmani. This frog is definetly duellmani, although it is slightly different than the one I have seen in the wild. Duellmani is pretty easily characterized by the parallel stripes down the back, but side and venter coloration is fairly variable.
The behavior you are describing sounds just like duellmani in the wild. I found them almost always in the leaf litter or a few feet above the ground in Guzmania bromeliads. As far as the orange goes, I saw frogs ranging from deep red to orange. So I believe it is a duellmani, but without precise locale information, it is hard to say exactly which morph. Do you have a picture of the venter?
The locality is on right river bank of Amazonas, close to Iquitos(left river bank).
I will make a picture of venter soon, but the color is yellow with a little of green. The same as duellmani, I think.
The call is very soft, several times repeted without pause between , approx. one second lasting each.
But I have received a picture of right duellmani and this frog has no orange stripes on sides and ventral pattern are connected to black stripe.
I will ask the author for permition to put the picture on forum.