Got some feedback from the seller:

"Good morning,

You're not the first person to mention this. The gentleman that is selling it is sure it's a 750 but after many people questioned it, I'm a little concerned. This one will probably come back to haunt me. He is a very qualified mechanic and said he built it from the ground up.
Thanks for your input and I hope it's as I advertised."

Chop whatchya got & ride it like you stole it!
Later!
Stephen