You would have to do more pictures to tell much, these three are inadequate.
The property marking is well explained in the thread dedicated to the subject, I suppose you have read it, so you understand the events surrounding it and its purpose. The "BS" is far less certain, though a thorough discussion has taken place here on the subject. Luckily Craig Brown was with us then and his invaluable contribution can be read; but we still do not know its meaning or purpose, persoanlly I think it is organizational, but it could be an ordnance depot, - generally it doesn't follow ordnance depot patterns for placement, but nothing can be stated with absolute confidence 1919-1932, however considering the multitude of police organizations, paramilitary (political factions), militia type organizations during this period anything is possible, Germany was a Banana Republik, politically unstable (an understatement) and its economy controlled by foreign states and banks. Generally I think that it is ridiculous to attribute collective guilt or characteristics to a culture or society, but if such a concept applies to any state, it is a tribute to the German people of the period that they held it together as well as they did, it may not appear to a casual observer that much discipline existed, but such an array of outrages have never been hoisted upon an entire society in such a sort period of time. It is amazing Germany didn't crumble into half a dozen individual states, - and they never really came close to doing so, though there were separatist movements in the Rhineland and Bavaria, but they were more a hostility to Prussian dominance than leaving a united Germany.
Anyway, try and do pictures of the matching components, especially the barreled receiver and rear sight, and if the stock matches it too (stocks tell you the most "if" they match). If it went through an ordnance depot it is typically on the stock, though in this period, if early enough, they sometimes marked the receiver with special markings or extra acceptance. The barrel, "BSI", probably means it is not original to the Bavarian manufacture. Amberg generally didn't use BSI, but ordnance depots installed Spandau made barrels marked BSJ (same as BSI), if the barrel serial lacks a suffix and the BC in front of the RS sleeve, it could be something Spandau worked, or an ordnance depot. In the Imperial era the state arsenals reworked rifles, though commercial firms in later periods did not, though in all periods old receivers were cycled through commercial firms to recycle this critical component. Detailed pictures will tell you more about what your rifle is, but these three pictures are of little use alone.
You may have to post a few times to add more pictures, generally you need to post three times to release the restrictions place on new accounts, - an anti-spammer measure.