Can an investor "assume" a VA loan?

I have several opportunities to acquire properties currently occupied by active duty armed services. They have VA loans and they tell me they are assumable.

Before I consider what to offer I am trying to find out the restrictions associated with these loans. Originally property had to be owner occupied with no down payment but owner qualified for credit. I have been told that these mortgages are assumable at their current rate but does the purchaser need to be qualified for credit and so the properties need to remain owner 0cupied? I would offer less is all cash but could pay more if I could take over favorable terms and not have to concern myself with credit and valuation issues.