I am beginning to understand that. The Yaesu FT-101 also has the SP-101P and a FV-101 along with it. My father bought them from a company in Hong Kong called Pacifica Products Ltd. between Oct. 1972 and Feb 1973. He was stationed in Laos at the time and they shipped them to him in care of the U.S. Embassy, Vientian, Laos via Cathay Pacific Airways.
I have all the receipts and shipping papers plus the manuals. The equipment is still in the original boxes.
My father set the system up and used it for about 2 months in Laos then it was all packed up and sent back to the U.S. when he retired. He never used them again.
There is a average looking used/working FT101E on Ebay right now with a buy it now of $419, and a similar used/working KWM2A with a minimum bid of $500 and an incomplete junker that is bid up to $300 as is.
What you have is almost certainly worth a lot more - so take good care of them and don't let anybody steal them. And if you do get tempted to fire either one of them up you should have the power supply components checked out because of their age. I think (though not positive) they are both only 600 or 800 plate volts but still blowing up a bad capacitor is a possibility and that would ruin their value.