mrcheeze,
Here is an example of a set of original RC red anodized retainers and a set of titanium retainers. As you can see, there is a SUBSTANCIAL difference in weight. If you have an accurate gram scale handy, throw your whole set on and compare your numbers with these below to let you know for sure what you have. Both sets of retainers came off big bore hipo engines that had a SUBSTANCIAL amount to of RC components in them, and both with RC stamped and ported heads. I measured the angles and shapes of both the RC reds and the titanium retainers, and the shapes and dimensions matched up perfectly. I have seen different shapes of retainers between suppliers, some minor, some significant. So though it's very possible that these titanium retainers were RC supplied, there is no way to be sure.
George