Good customer service! The new carburetor, for Husqvarna 445, was found to have a different gas inlet fitting orientation than original. All other external fittings were the same. Customer service verified correct part was ordered for saw serial # and checked further back into supplier data base trying to confirm reason for change (still unclear). Ultimately, the new carburetor was installed (with a slightly longer rubber connecting tube) and found to work. Chain saw is back in service.
While the exact cause for discrepancy was not found, I was very satisfied with the effort that went into trying to find out "why". Thanks Jeff!!