I think so. I believe your CVI could would look something like this:
/* first get handle to engine */
TS_SeqContextGetProperty (sequenceContext, NULL, TS_SeqContextEngine, CAVT_OBJHANDLE, &engineHandle);
/* then get handle to profile you want */
TS_EngineGetUserProfile (engineHandle, NULL, "Operator", &userProfileHandle);
/* I'm a little fuzzy on this part - not sure if you can use the get/set property functions at this point or not */
TS_PropertySetValBoolean (userProfileHandle, NULL,
"Privileges.Operate.Execute", 0,
VFALSE);
Good luck, Mark