It has to be near impossible to tell the strain just by looking at 4 week old flowers. Best that could be said is whether the plant has more indica background in it than it has sativa.
@013 looked into it and he has reported that there are upteen thousands of different strains that have been documented and talked about.
What we know is that it is a Random strain which is a good one to start with. Nothing wrong with growing the Bag Weed strain either. I would not be surprised to find out that the Bag Weed strain from 50 years ago is the great grandma for most of the seeds of the popular strains we pay good money for these