Do telomeres appear at just one end of the chromosome?
This is a great question!  The issue- the "paradox" of replication of linear chromosomes- of trying to filling in the unreplicated region (an overhanging 3' end) should technically be an issue only for one 3' end of each chromosome on any round of replication, as one new 3' end is produced by leading stand synthesis, and the other- the one with the issue- by lagging strand synthesis. However, both ends will have telomeres, they simply trade off being the end with the issue, in each round of replication.  Or you could say, in a single round of replication, one sister will have an issue at the right end end, and the other sister will have the issue at the left hand end.