Yup, that's where I found the other two, but the 'missing' one bothered me.
Just got off the phone with both Cummins & Monaco, and they confirmed just the 2 of them (FS1022 & FF5488). I now believe there may have been a transposed letter in in my source-data, or he was just confused.... Cummins did verify that there was/is an alternate for the FS1022 - and it's a F
S1003 - and NOT a F
F1003 like the OP said, but the horse's mouth(s) disagreed.
So there ya have it.