Can I put 2 male hamsters in the same cage again?

I had two male hamsters since February, at first they got a long great, snuggled together and everything. Then a few months back they started fighting and I eventually had to put them in two separate cages, they were both very injured. Now they're both fine and healed. My mom went to the pet store recently to get another cage and an employee said it was ok to put them together again and it was just a phase? Is this true?