Copy of shaping does not guarantee meaningful results, and neither it is possible from photos. Lot of minute structure-related details are not apparent in the photos, mind you. Types of materials in use, types of bolts in use, zigzag touches, platform alignments, quality of RAM coating, engine-related considerations and making the structure unstable - herculean challenges on the whole.
Engine of F-35 is also different from that of F-22A Raptor - difference in the rear section is compensated in different ways.
F-35 Block 3f have uniform RCS of only 38 mm - the size of a bee.