If you make a major change in your playing style (such as learning to slap) then it is entirely reasonable to setup your instrument. Or it may just be the changing of the seasons; your bass was setup for winter, and now that the weather is warming, it needs another setup?
You can save a lot of $$ by learning to do a setup following these guides: ALL BASIC SETUP QUESTIONS ANSWERED HERE
On the other hand, since you are new to slap, it is entirely possible that there is nothing wrong with your bass/setup, but rather, you simply haven't mastered the technique yet. Do you get the fret buzz slapping, but not when you play with fingers/pick? In this case I would recommend that you practice slapping with as light a touch as possible so you get less string/fret noise. Being very gentle and economical with your motion is the key to slap technique, in my opinion/experience. Also don't be afraid of a little fret noise; it may be unpleasant when you are playing solo in your bedroom, but it tends to disappear in a full band mix, or even help give the bass some extra "growl" to cut through the mix. Go on Youtube and listen to islolated bass tracks by Geddy Lee, John Entwhistle, etc. and you will hear a ton of fret noise.
I am a little concerned that you do not mention a teacher. Working 1-on-1 with a good instructor is the best way to identify and correct any flaws in your technique. A DVD cannot look at your hands and make suggestions.