Wow that was quick response. Unfortunately it measures out to 16.5 inches. That 2 inches two short for a long guard.
However, I still think this is a real Cat guard. I think
Cat actually made a "long-medium" guard that was mainly used on the JCPenney's Duster and small JCPenney mini bikes. They were shorter than the "long" Cat guards (18.5 inches) and I want to say 16.5 inches is about correct because the Duster had a smaller frame. Look at the Dominator guard photo and compare it to the Duster guard photo below (credit to f4radar for Duster photo). The Duster guard does appear to be about 2 inches shorter.
Conclusion: I'm going to say this was probably a replacement Duster guard bought at JCPenney's a LONG time ago. It's a real Cat guard it looks just like the factory ones and I don't see any obvious signs of modifications. It's not a Cat "long" guard but can work on some Cats. He also has a replacement blue guard that went on the blue Cat JCPenney mini bike for sale too (see photo below of blue guard on JCPenney mini bike).
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