It's true. The eggs just wont be fertilized (meaning no babies). If you have a female make sure you have a proper laying bin, or else they can become egg bound.
Male panthers can grow to 20 inches in length while females mature to a smaller size of 12 to 14 inches. It all depends on the individual panther though.
Any of the oviparous chameleons and this includes female Jackson's can certainly give birth to unfertilized ova just like their egg laying sistren. It doesn't happen often but it does happen.