Scrizo and I was discussing this last night so I just wanted to give everyone else a heads up:
Your level 50 weapon that is upgradeable to 60 will be the best one you can obtain since there will be no 2-carat diamonds within the game which are needed for upgrading. Therefore, do not even bother obtaining Lv. 58 weaponry, Lv. 53 is pretty much optional too unless it has some sort of bonus. So don't waste your time or money making them or even getting the recipes unless you just want to have.
Here is the forum thread discussion where Admin ittoujuu officially states it (on 2nd page):
http://forums.aeriagames.com/viewtopic.php?t=424944