Thumper and Bella fluctuate between a pound here or there each time I bring them to the vet. Sometimes it is up and sometimes it is down. However, I do not free feed as Thumper would eat the entire bowl if I left it out
If he is in the normal healthy range I wouldn't worry too much and just keep an eye on it.
You might want to buy a scale yourself so you can weigh him periodically to make sure he is not losing too much weight. I did that when I had Boomer and he was sick. I just bought a baby scale off amazon and it worked.