This is a Chromed CB450 CL450 sidecover . CB and CL450 models shared the same sidecovers. In stock form this part was not chrome. There are a couple of Honda theories out there. Honda had some all chrome bikes that they let brand new dealers sell as a part of their grand openings back then. This could have been one of those. If not, it was just chromed. It was a lot less expensive back then, and lots of people had things chromed
The label says CL450K1 but it is a K2 and after as you can see where the K2+ badge indentation is located. It is hard to take a chrome picture. You can see my hanging bicycles and other reflections. However, I can tell you that it is as close to new as you can find.