Interesting turn of events from an old listing. Turns out the Diamondback Tactical XSP1012, an old commercial XSAPI, and LTC 28601 XSAPI are the same plate. This also means the 28601 is much older than originally thought. This one is from 2009!
Bad news is that the XSP1012 IIRC is an ICW IIIA plate, so a long-ago deleted Hoplite post may be correct in stating the 28601 is NOT standalone. This also means Apex is wrong... again.
Since the 28601 is now apparently a sixteen year old model, it's basically a REV. A XSAPI but swimmer cut and 0.25lb lighter. In other words, pretty good for 2009.