Based on what I see, I find it difficult to imagine that getting caught on anything. There really isn't anything that goes around back there, but if you feel like putting the effort knock yourself out. I used to completely overhaul every bike I bought, and now after I've started working as a mechanic and I see people come in with bikes that shouldn't be rideable, and somehow they shift just fine... it has definitely lowered my standards. As far as a learning experience though, it is definitely worth it, just make sure to have a nice set of pliers around (needle nose my favorite) and be ready to get pissed at it. That specific part (the B-tension spring assy.) is the most annoying part to have to disassemble on a derailleur. It is interesting to see that I took apart a 30 year old shimano derailleur, a 10 year old one, and a brand new one, and they all have the exact same pieces and are put together the same way. This is true across brands (for the most part).
Given the prices of parts I have ordered from Shimano before, it might not make any sense to order just that part, being that a 9year old sora derailleur probably wouldn't cost that much on fleabay anyways. I have completely overhauled a ton of derailleurs before (completely disassemble, re-grease etc) and honestly.... it has never been worth the effort. If it works fine.... I don't get the point. If it feels bad though, knock yourself out. I do it sometimes just because I find it therapeutic. It is worth the time to clean the outside though... for pure bling factor.
A sora RD on ebay runs new for $30, so keep that in mind. (including shipping)