@RoscoeD
I actually bought my polymer guide rod from CZ Custom as i was buying a few other parts i needed for other guns and the guide rod was only like $3.50 so figured why not give it a shot. I had previously read other people were using them in their Shadow 2's to make weight. It's clearly listed as the SP01/Shadow guide rod in CZC's site and no mention of Shadow 2 compatibility. But at any rate, yeah i experienced the same thing you did. Oh well. I think I'm going to get lighter grips to make weight instead.
If you get a scale (they're honestly really cheap
) I'd be interested in how much your slide weighs with no barrel or recoil spring assembly. I had my slide cut by Primary machine with a front window but it's a different style/design of cut compared to what I've seen CGW and CZC doing so I'm curious how they compare in weight.