I worked for "the utility" for many years. The answer to your first question is probably not. The utility engineer might be aware of the number, size, and lengths of the secondary conductors but typically he wouldn't know and wouldn't care. His responsibility ends at the the transformer secondary terminals in most (not all) cases.
The bad news is that if you asked three different engineers from this utility for the fault current you might get three different answers. Did they calculate using actual system impedance or did they assume an infinite bus? I did both but usually the latter, which will produce a slightly larger number. Did they have the transformer nameplate data or did they just use 5.75% or some other "good guess"? I always made an earnest effort to get the nameplate number, but had a good feel for what to use when I couldn't. You might go back to the utility with these details and ask if a recalculation is appropriate. And whatever their final answer is, be sure to get it in writing.