yes, the first three times you complete the RT side quest at S rank you get a piece of the "custom" set, and the fourth you get WORKS guard: http://www.pso-world.com/sections.php?artid=2414&op=viewarticle
The vulcan and the caliber were taken already but you can definitely have the sacred bow I'll be available in an hour or two today but if that doesn't work just let me know when you are available