The Cno7 was a training version of the no4mk1*, and 80% of the no4 parts are identical on a Cno7.

Walking away is the right thing to do, although photos are always welcome. The rifle described in your post does not pre-date no7 production as that started in 1944. The lack of a serial number is a warning flag, and even if it is a factory production rifle (which I personally doubt), the price is still about double what it should be, assuming you are talking US dollars.

Here in Canadaicon, I suspect the market value of a factory, in the chest, in the grease, un-issued rifle with it's tag and EIS, would fall into the $2500-$3000 Canadian $ (peso) range. I say suspect because they don't come up often enough to put a fixed price on them, and there will always be anomalies.

My apologies to the current owner of the rifle if he is on this board, and I would love to see some good photos of the rifle in question.