OK, so your 7T5439 Link is original and part of a 40-link sealed & lubricated 6.91" pitch track setup for a 953B.
For the 953D there are both 6.91" & 7.50" pitch track options available, so everything depends on information to find whether or not they will fit your 953B.
As I mentioned before, getting link Part Numbers and how many total links in the chain will be key.
Also can you get some photos of the tracks.?