Yep, the plastic should be the same. The main thing I check is the gold plating; the Mill-Max is 30.0µin (0.76µm) thick, and the Preci-Dip is only 29.5µin (0.75µm). So you are getting 0.01µm less gold on the Preci-Dip part, but saving $4. I wonder what the margin of error is on that measurement ;)