Indenting on the right but not the left is a very common practice.
There's room on the left side for the chainstay to bow out, but the right is constrained by the chainrings. That's why you'll often see indenting on both the inside and outside of the right stay.
Your bike is probably, but you'll have to live within the tire size limitations. Try a 1.9" tire and you should be fine.
BTW- I'm assuming that you checked that the wheel is properly centered based on the seat tube. To make sure you can lay a yardstick on a secant across the wheel and measure to the seat tube. Repeat on the other side and the numbers should match.
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