It's not a CSWE (MSW) requirement, but it would be good practice for any mental health professional to become familiar with commonly prescribed psychotropics and their effects (expected and otherwise) on their clients. If you do a quick search I believe a thread on this topic was previously started some time in the not so distant past.
I'm finishing my MS in CMHC also CACREP and in my program there's no pharmacology course. However, in my adult psychopathology class medications and the brain is covered. I guess the best way to answer this question is to look at the curriculum of the school you plan to attend.
Well if it is you scope of practice to understand pharmacology, then go for it. I don't assume that my understanding of something that is outside my scope of practice to be the same as a trained professional. If I get a suspicion that a client could benefit from speaking with a prescriber about their medication, I will give that recommendation. Then again, it is always prudent to work with other medical professionals on behalf of the client if the client is open to it. In my state, in my training, I cannot assess anyone's medical condition or how their medication is working for them. I can always encourage the client to seek expert advice.