There should be some good life left in them in my experiences. Usually you have one cell that goes bad and causes the whole pack to fail.
That’s not always the case but is more of what I have seen. I have never had this particular pack though.
According to what I looked up the cell was rated at 1500 mah and I would guess its a bit under that now from all the use and age.
If you have a way to test them that would help to determine if they are still good cells.
This is just my opinion, but at that low of a capacity and the price of good new higher capacity cells I wouldn’t have much use for them.
You might have a use though. 
Almost forgot, if you have a dremel tool or something similar you can buy sanding drums that will get rid of those spot welds with ease.
https://www.amazon.com/Jumbo-51pc-Drum-Sanding-Kit/dp/B007FER2IW