there are many many many 6dj8’s and equivalents... it was a popular tube, used in many applications, consumer, commercial and military, and was made all around the world up to the point where tubes were supplanted with solid state devices in the 80's and 90's
if the tube is in fact in the audio circuit of the op’s dac in a meaningful way as @lewm mentions, there will be many many different sonic presentations available through rolling different 6dj8’s
i still have hundreds (no exaggeration) of old stock 6dj8 variant tubes, made in usa, uk, holland, hungary, japan, india, slovakia, russia and so on... as i used conrad johnson linestages for many years, and they exclusively ran that tube in their better models for 20 years