4th Gen Model M. 42H most likely.
Like the other's have said, the LED's are integrated into the controller, and the cord is not removable.
Are you saying that your LED panel is different because of the style? It IS different over the first to third generation Model M keyboards, but otherwise, it's still a good keyboard.
The terminal models have no LED's at all, but can be made to have them if you have a spare 1391401 controller and a drill handy.
https://imgur.com/a/O7ayYThis is an easy mod and very cost effective.
Edit: The keyboard in the example above is the one I am using full time. I keep answering the thread "What keyboard are you using now?" and repeatedly post the picture of THIS PARTICULAR KEYBOARD in the comment. I wonder why.
This next example goes into more detail as to how to do the LED Panel so it looks like it was there all along.
https://imgur.com/a/bBFuvHave a nice day!