both species have fibers. Some look identical at this age, though some filiferi have an incredible amount of fibrous material... however, so do hybrids sometimes.

I agree with lzrddr, when they young its very hard to tell. Where did you buy this palm? If you bought it from the West coast it can could be any of them. But if you bought it from the east coast it will be a robusta or hybrid. The CA fan palm does not like humidity and is extremely rare outside of dry climates.
- US_Marine

I got it from a seller in Florida, he said it was a robusta. I put it out in full sun and the fronds started turning yellow. Don't kno if it's sunburn or just shock from the transplant. I cut 2 of the worst fronds off n was left with 2 plus the spears, I'll post a pic, I since moved it to part sun instead of full sun, any ideas of what could be wrong?

These tend to transplant poorly at that age... But it still might make it... give it some time.

I agree, filifera is not good in the East. I once planted dozens of seeds of robustas or filibustas, and filiferas. All the filiferas ended up dying; no problem with the robustas or hybrids. Regarding the yellowing, how much are you watering? In Summer, in full sun, in high heat, these are water lovers, and small pots dry out quite fast, so watering everyday might not be excessive.