Over the years Remington has made quite a few versions of the Mountain Rifle not all even called by the name even tho in all respects they were. The CDL Model 700s all have a heavier contour barrel but same contour stock as the Mtn. Rifles.
The original Mtn. Rifle had nice grade of walnut and was of normal BDL magazine type. They also made some with nice synthetic stocks in ADL configuration. I've had two of those. Initially they were long action only in .30-06, .280 Remington and .270 Winchester.
A few years back they dropped that one and went to the detachable box magazine rather than BDL magazine for them. Otherwise they still look like the originals.
Now the LSS Mtn. Rifle is the primary Mtn. Rifle tho and other than the metal being SS and the stock being laminated they are basically the old Mtn. Rifle in all other aspects. They have been made in .30-06, .270 Winchester, now in .280 Remington, 7-08 and .260 Remington. I've own all but the newer .280.
The CDL is available in most everything Remington chambers. BUT they come with 24" not 22" barrels. All Mtn. Rifles have always had 22" barrels.
In the Model Seven line they originally had 18.5" barrels then went to 20" and when they added magnums they had 22" barrels. The standard Model Seven CDL has 20" and 22" on magnums. The new 25th Anniversary Model Seven is chambered only in 7-08 and has a 22" barrel and a different checkering design than the normal CDL but other than barrel length and checking pattern it is basically just a CDL. Yup got one of those too.
I would be interesting in hearing just what the rifle is if/when you get it or even if you don't. Perhaps they've slid one in on me I've not seen yet. They do that some times.