I can’t remember exactly the diameter of the lower shock bolts, but I know they are definitely metric.
Everything on stock Fords is metric.
That said, some American aftermarket parts like top strut mounts may be SAE if they've been replaced
PS ~however~, with big-ass bolts like 30mm the metric/SAE distinction becomes moot... if you can't find a 30mm deep impact socket, 1 - 3/16" deep impact will do JUST FINE.
Also, not sure if this is the case for you, but afair on my 3rd gen the other side of the nut/bolt pair that needed the 30mm was a 27mm... this too is also approximated just fine with a 1 - 1/16" SAE socket.
If you're having trouble finding them, SEARS is one of the few brick and mortar shops that still stocks a variety of socket singles past 20 mm and 1".... They had something that worked out every time when I needed 27mm, 30mm deep, 32mm, and 36mm.
However, even their selection is dwindling, so if you're not willing to spring for a large expensive socket set, you'll often have to go to a SAE approximation of metric or get something not as deep as you wouldve liked and/or non-impact....