Does the M2A2 During ODS have the thicker armor? I have here the ODS M2A2 by Tamiya and it has two side armor - a thicker one and the standard. Does both of these seen war during ODS?

The M2A2 has thicker armor than the M2 or M2A1. The M2A1 and M2A2 both saw service in Desert Storm. The M2A2ODS did not exist during Desert Storm. It was developed after lessons learned during combat operations in Desert Storm were applied to current M2A2s. Several stateside units deployed to Saudi Arabia with the M2A1, most notably, the 24th Infantry Division (currently known as the 3rd Infantry Division from OIF).

The M2A2 adds steel plates to almost the entire outer surfaces to stop 30mm AP rounds. The bolt heads you see on A2 plates are for mounting ERA blocks. As such, the M2A2 IS 30mm AP survivable right then and there without add-on armor. Not many ERA block kits were made for the M2A2s...about 100-200 AFAIK were ordered. Chances are the steel plates will take damage from 30mm rounds, but they could make 14.5mm AP rounds just bounce off. I'm not sure of this, nor do I know if the rounds reach the main hull.

The M2 and M2A1s without the boltheads survive against 14.5mm AP rounds and as such, take damage in the side skirts if hit (like body armor taking damage). Most of these are in the National Guard or Reserves.

With both M2 and M2A1s, the idea is to stop the 14.5mm AP round from even reaching the vehicles' hulls.

The "rounded" parts in the M2A2ODS kit are there only because the whole sprue with them came from old Tamiya M2 model. They are not supposed to be used with this new kit. And you cannot build M2 model from this kit, as the hull part is different.

Rgds,
Pawel