During the earlier stages of the war, a number of manufacturers built MG34's. After the MG42 was developed, they all started switching over to the 42 and then stopped making the 34 (with some exceptions). There was still a need for 34's, however (armored applications and fortifications, etc.) so some were still made and one manufacturer stuck with the 34 instead of switching over to the 42. The last factory making 34's was Waffenwerk Brunn in Czechoslovakia (code "dot"), which made them until the end of the war in 1945. (The Germans occupied the Brno factory very early in the war and converted it to their production. The German name for Brno is Brunn.) It stands to reason that 34's made later in the war had a higher chance of "surviving" since they were around for less time and had less of an opportunity to be destroyed.
From all that I have read on the MG34, I do not believe that any were manufactured post war. Certainly, MG34's were sold off and used by certain armies post war. That might have included parts that were made in 1945 and never delivered to the Germans. The Brno factory was overrun, but not destroyed. I have not read about a single shred of evidence of actual post war manufacture, as opposed to assembly. (The 34 was a very complex MG to manufacture, as well.) It is quite common to find 1944 and 1945 dot coded barrel shrouds with Israeli property marks (5 pointed stars). I have copies of a few pictures of Israeli forces during one of the major Arab wars where MG34's are mounted on their vehicles.
With all of that said, I have not seen any extra value placed on 1945 dated barrel shrouds. If anything, because of the history of manufacturing, a lot more 1944 and 1945 dot guns survived relative to the total number produced during the war. It is very common to find dot coded shrouds. So, no, it's not like 1945 k98's. There is no "late war" or last ditch premium to be had on the MG34's from 1945.