It has the brackets for the top bows on the driver side.....that points to a 2a tub..
If you can get the seller to measure the wheel house the 2a's is a couple inches longer than the 3a...I do not remember the specifics though...about 32 vs 34" comes to mind ...
Also a picture of the dash might show the key/ignition hole in the dash..a 2a will have the hole on the passenger side of the shift lever.....
Can't really tell from the pictures but if the front engine mounts are off-set i.e. the driver side further forward from the passenger then it's a 3a frame...if they are even it's a 2a...
Ya can't beat that price!!
This will give you more info..
http://www.cj3a.info/cj3a/cj2acj3a.html