If it's paired-end you should have two files ( R1.fastq and R2.fastq). In the id of the read you should have an information about the pair. Here an example of one pair of reads; The information is at the end of the read in 1 :N:0:28. The 1 represent read from R1.fastq. FYI, it's from a HiSeq 2000 run
So in your example, it should be single-end data..