It’s a switch mode supply and most likely pretty noisy, so it may not be very usable for an mbSID. At that price you can always get one and try it though
“Missing” -12V may or may not be a problem depending on what you plan to use the PSU for. For mbSID, LC, SEQ, … not a problem. mbFM or anything using seppos SSMs - problem
If you connect it wrong, you can certainly break stuff. If you don’t it’s fairly unlikely. Make sure to meet the PSUs minimum current consumption otherwise it might give you wrong voltages.