the SN 387 above is not chambered for the 6,5x55 but like the other in 6,5x58RD.
got this about the Model 38 and the problem today to determine the correct caliber

"Model Number 24 (from 1924) was developed as a rifle for shooting range
and competition in caliber .22 – it is the first rifle where every component was
manufactured at the factory in Otterup.
In 1938, Model 38 was introduced in large calibre, as a hunting rifle, with
three cartridges in the column magazine. Like the Model 24, the barrel,
action, stock, open sights and tigger was made at the factory in Otterup.
Lowest know number : 128
Highest known number : 421
Niels Larsen, from Schultz & Larsen, had participated in the Olympics in
paris, 1924 and won a Bronze Medal in the 600 meter free rifle discipline. At
this event Niels Larsen noticed a rifleman from Estonia, carrying a rifle , that
inspired Niels Larsen to develop a new rifle with 4 lugs design, locking the
bolt securely in the action.
A good part of the first rifles after model 38, including the prototypes, are
marked with the following markings : 6.5 & 6.5R on the barrel. These
markings has been a bit of a puzzle and have generated lots of questions
over time. Solving the puzzle has been a real challenge and taken a long
time, because all the original gunsmiths of Schultz & Larsen are long gone.
We believe that the puzzle may have been solved, especially by looking at
the material gathered from knowledge of ; Model 38, prototypes and
Mauser/Otterup.
My dad, and many other have used the Danish Krag Jorgensen Model 89 at
the shooting range. These rifles had been fitted with new barrels,
manufactured and fitted by Schultz & Larsen in caliber 6.5x58RD
It is my believe, that a good part of these barrels, have been marked 6.5 &
6.5R on the barrel, but without actually finishing the barrels before 1945. The
rifle bore is always made before the chamber, and in this case, they have
been finished in the new 6.5x55mm caliber instead of what was first intended.
6.5x55mm came to Denmark with the return of the Danish Brigade on May
5th. 1945 – they all carried the Swedish Carl Gustav/Husqvarna/Mauser 96 in
caliber 6.5x55mm (swedish)
In cooperation with his sons Uffe and fritz Schultz Larsen, both Engineers,
Niels Larsen developes the model 38, 1938 for hunting. It has a full length stock
(carabin) and later a model for the shooting range called model 48, in 1948.
These models can be found in the following calibers : 8x58RD. = 8mm =
8x58Krag og 6,5x58RD.
RD = R for rand, D for Danish.
The bolthandle can be found in a ball and a flat design"

so the barrels laying on stock marked 6,5& 6,5R for use in the caliber you need and this confuse today.

the same man doing the same work no matter which action was on hand
http://www.lauritz.com/da/auktion/mauser-k98-riffel-med-otterup-pibe-kal-6-5x54/i4881205/#
Mauser 98 in 6,5x54 post war sporter from Otterup