Any design can be reverse engineered by a capable lab. The tough part is duplicating the manufacturing processes and tolerances. Give an engineer the gages and metallurgical testing equipment and they'll produce a good drawing of any component. How to make that part creates a considerable obstacle. Now if the copy cats get a full copy of the manufacture's specification's and drawings via industrial espionage then they've got the full description of the part. Komatsu did a good job in the '70 & '80 of copying Cat's machines. They were typically a couple iterations behind Cat's current offering, but they pushed dirt and sold for 50% of Cat's price. All manufactures do competitive analysis to understand the design and features of other's products. Cat buys and dissembles all their competitors machines to benchmark their offerings It's a normal part of doing business.