As you stated, the code says to omit arrows from vectors if both bold type and arrows are used in the construction, unless the author calls special attention to them. I would say in this case that the arrows should be retained.
Sec. 35 of the Nemeth code says the use of 456 before operation or comparison signs to indicate boldface is limited to those signs provided for in the Code. Rule XIX provides for boldface plus and minus signs [braille]_+ and [braille]_-. Rule XX provides for boldface equal sign [braille]_.k
I am looking into the problem of the boldface multiplication sign.