The above answer is correct. That is to say, sorry, but he is completely wrong and he doesnt know anything about Floyd Rose trems. (Maybe next time, offer facts and experience and not opinion...)
Regarding the Original Question:
There are many design parameters that have to be considered when making the swap from any Liscenced floyd to an Original or FR 1000. Some of these are the length and type of allen bolts. Saddle material. Size of the back plate. Size of the block. (matertial of block). Alignment of the springs to the trem cavity (backside route width and depth). Fittment of the plate to the studs. Can you replace the studs with similar threaded, etc... All presuming you wish to avoid going at this with a rotary tool in hand and carving out the routs for designed fitment. Floyds are tricky beasts. Installed correctly, theyre amazing. Installed with ignorance, and your results may be much less successful than expected.
Here instead is a site with excellent information based on facts and user experience which should help you out.
http://audiozone.dk/index-filer/TremoloInfoProject.htm#jt580
In particular, the swap you describe (replacing JT580 with OFR) has been done successfully and the pictures are posted here. Keep in mind the caveats I mentioned above. You will need to check the depth and width of the route on your particular guitar. If you have a thin body, the block may not accomodate nicely. One user's success does not mean it will work for you. So check to see how his project compares to your own. But at least its good to know that it has been done successfully! (JT580 to OFR replacement).
cheers