Richard, since no online vendor lists this information, I would contact Leupold Customer Service with the model# and UPC code at 1-800-LEUPOLD or by online inquiry here : leupold.com/service-support/contact-us

You know what, I’m not even aware of a series 1 or series 2, if any. I own several Leupold scopes and never heard of such thing. I know the model #177910, which is the one you’re talking about, but not about any other series. This seems to be the newest version. Then again, there are so many optics it is difficult to keep track off. Here is Leupold’s contact number: 1(800)538-7653. Calling them will get you the best answer. Hopefully, another member here can be more helpful. Thank you.