Can you ID this Mopar gearbox?

I talked to the seller and no ID tag on the gearbox body. He told me that the trans is out of a 170ci Barracuda. I think it's a '66.
He sells the complete trans, plus the bellhousing, the clutch and mecanism, the speedo cable, and a driveshaft.
Appears to be a good bargain at 500 euros.

I found an excellent information about slant-6 A833 & OD A833 :
4 Speed Transmissions transmission

Now, the bad news :
This page tells about a "hump" into the floorboard for 4-speed transmission, to clear all the shift rods.
I don't know if my factory 3-speed floorboard has this hump, or not... The shift rods on the A230 are under the gearbox body and do not really require a hump into the floorboard.

So, the question is : are 3-speed and 4-speed floorboards the same, or not?