I'd called on it, asked for photos of the proofs, breeches, flats, and muzzles.

I've deleted them, so if you want to see what I'm basing my assumption on you'll need to call in and request some photos for your own perusal.

If you do go ahead and do so, note the above mentioned features of the gun.
Also note that the chambering is more likely 7x65 and not 7.65

500N, to answer your question
"Why spend $3500 on that when you can buy a new
SxS 9.3 x 74R for similar ?"

For one, on my end of this thing there is no why.
I'm not looking to buy it, nor was I looking to buy it.
Someone asked me to call the shop and ask about it.

Also, if it is indeed 7x65, a good reason would be that it's not a 9.3x74R
This thing, if it is a 7mm rifle, might be a lot lighter and livelier than the mighty 9.3

A question for you.
Who has a 9.3x74R SxS double rifle with two triggers for four grand new?
Sounds like a deal!

I'll see if I can get the photos from the guy I'd sent them to, I'll post them if he's still got them in his email box.

--Tinker