The problem with the JK factory is that the pushers are NOT asymmetric- this is the key to a correct 6263 or any watch in that series which originally used a V72 movement. This would include the 6234, 6238, 6239, 6240, 6241, 6262, 6263, and 6265. DW cases had the correct asymmetric pushers and could use the 7750 movement, but DW is gone and no one has come out with the correct case for a 7750 since then. And finding a DW 7750 case is tougher than finding hen's teeth. The only cheap option is the cartel with the Venus 75 movement these days.
Look at the 6238 on top in this picture- see how the top pusher lines up with the two o'clock marker and the 4 o'clock pusher is slightly below the 4 o'clock hour marker- this is what we call the asymmetric pushers- key to any good vintage Daytona build. BTW, top is a gen 6238 and bottom is a Phong 6238 with V72 movement and Phong dial.