It depends on who's calling them out and how particular (anal retentive) they are. According to A563, A194 Grade 2H is acceptable substitute when properly marked to A194. When zinc coated, the overtapping, lubrication and rotational capacity shall be tested to A563. If they aren't coated, I would see little trouble in showing a QA type that the requirement is met with the much more common A194 Gr 2H if there is any difficulty finding the fasteners marked to A563. If you need them marked to A563, then you should look for a fastener manufacturer such as Cardinal in Las Vegas, Nevada who can make (mark) them legitimately.