jb;
According to the references available to me, only two suffixes will be found on German acceptance marked Hi-Powers; they are suffix a & b and will be found on WaA140 stamped pistols. The b suffix ended at approx 63000b, therefore your pistol would fit into the b suffix range and would have been assembled quite late in the occupation. Both wood and bakelite grips are correct for your pistol as bakelite did not replace wood grips, merely supplementing their use. One help in dating your pistol; in the spring of 1944 the manner of serial numbering the pistols changed. While the slide was stamped with the entire serial # and suffix, the frame was only stamped with the last 3 digets of the serial # + suffix.
WaA140 Hi-powers are the most common encountered, however, the standard wooden grips are more commonly found than the bakelite.
Good Hunting