I guess as long as it isn't victim of a direct blow of receive any extra vibration like from an earthquake or something it should be fine. I tend to overdo it with installations if I can within reasonable means (I'd rather just use toggle bolts than drill half a dozen holes looking for a stud, since stud finders aren't reliable).
BTW, I got the first clock working! The motor arrived at school today and I've been storing the clock at school, knowing that the motor would be coming in. Anyway, the clock works (and is silent now! lol) and it should sync properly. The only thing I'll have to worry about is if the hour hand is in the right spot (since I took the hands off, I can't know the correct position until it synchronizes with the other clocks and then the hour hand can just be manually pushed to the correct spot. I set the clock two minutes behind the actual time so that it would synchronize within the hour, but the hour hand might end up being off. The reason is because the Master Clock tells the clock to behave in a certain manner (i.e. makes the gears turn so that the clock reads a specific time) but if the hour hand is two hours ahead of where it should be positioned, the Master Clock will think it's reading the correct time and assume the hands are positioned correctly. The Master Clock controls the gears, which controls the hands, so if the hands are not positioned properly, the clock will synchronize to the wrong time. The minute and second hands will synchronize without issue though.
Hopefully I positioned the hour hand properly when I put the hands back on the clock, but if not, it's an easy fix. Just unlatch four springs to take the crystal (glass cover) off and manually turn the hour hand to the right time with my finger (the only hand of the three where you can do that; the others must be set by falsely triggering the gears or else you'll screw up the gears and strip them or screw up the alignment.) The second and minute hands work together but the hour hand is actually independent as far as the gears are concerned. So changing the second or minute hand will also change the other, but changing the hour hand does not affect either the minute or second hands. They're very complicated devices lol. Very expensive to maintain too! We ordered the new motor from a company called American Time, which is a great reputable company that sells Simplex parts for our Simplex clocks. The motor cost $30! A new clock however, costs nearly $200! I haven't checked the whole school yet, but so far there are around half a dozen that need repair and one that is totally missing (the PA box has an open cavity where the clock is supposed to be) so I'll have to check with the principal if he wants a replacement unit ordered for it or if it was intentionally removed for some reason.
The Clock system was serviced once since it was installed in 1998 and the defective clocks were simply replaced with American Time units, which I assume are cheaper than the OEM Simplex clocks and are designed to the same specs (major manufacturers' clocks are not interchangeable though; but American Time makes mock-ups of all the major brands so we can order Simplex-compatible clocks for the system). I'm not sure when this servicing was done, but all but one of the newer American Time clocks I've seen still work. All the failed ones are the original Simplex clocks, which is not surprising given the system is over 15 years old and any form of maintenance on them is unheard of, so dust builds up inside the clocks and makes the gears bind and the motors fry and then you get the one or two teachers who think they are mechanically-inclined who think they can fix the clock but f*ck it up (fortunately it was just one in the gymnasium locker room that was tampered with so far; the whole gymnasium building has a wiring issue though since all the clocks work but display an incorrect time, so the clocks are not receiving communication from the Master for some reason). I will tell the principal that I cannot fix the gymnasium building clocks since the issue goes beyond the clock itself and will recommend that a work order be placed to have a technician troubleshoot the wiring from the main building to the gymnasium.