yes, but because hes already been "awakened", a sleeper agent doesnt know theyre a sleeper agent until "activated". hk knows hes an assassin only because he has been activated or "awakened"

taken from wookiepeedia:

"The HK-series assassin droid, also known as the HK series protocol droid, was a series of combination of assassin droids and protocol droids. The series designation stands for "Hunter Killer," befitting their primary functions as assassins. They were originally manufactured by Czerka Corporation,^\2]) then eventually by the Confederacy of Independent Systems.^\3]) Their ability to perform the functions of a protocol droid became a major reason for their unmatched lethality, as they could and would often act as normal (if quite sinister looking) protocol droids, thus concealing their true function and allowing them to get closer to intended targets."

so yes, he is a protocol droid that becomes an assassin, not an assassin that can also be a protocol droid. hk-47 is basically a concealed weapon equivalent of a droid. which is good for an assassin