Can blockage on one side of the male reproductive tract be roughly determined by sperm count and hormone level?

Probably not: It would be important to know how the one sided blockage was diagnosed, because knowing that will help answer your question

Yes and NO: there certainly would not be a change in hormonal production but the sperm count could be affected but NOT DROP to levels which are insufficient to impregnate! Hope this helps! Dr Z

It is unlikely: that either would be predictive.