The screws are metric, amazingly.
M4 - .7 x 14mm with an undersized hex head and flange. Home Depot sells M4-.7x12mm in either pan head Philips screw with a head about the same size as the original flange, or a hex bolt with a much larger head. The 12mm is a bit shorter than the original but should work OK.
I am glad that you brought this up, I needed a couple myself.
With luck, the new threads will re-mould the insides of the sleeves, at least partially.