Q: If playing with combined Star Trek TOS & TNG decks, for the Goal Standard Gear, which calls for 2-out-of-3 items, can I win with two of the same item, from different eras?

A: No, though there are five potential Keepers which could help you achieve this Goal, it doesn’t become “any two out of five” it’s still “any two out of the three types, we just don’t care which era.”

You need two of those three types of equipment, regardless of when they were manufactured. If you want to think of it thematically: two of the same item are not going to be terribly useful when your goal is to be well equipped.