The CPU and GPU temps are a bit high for Idle. You may want to upgrade the cooling on the CPU and airflow of the case your using. As for the graphics card, not much you can do other than buy a whole new one with better cooling.
Im guessing that room temperature is around 20 Degrees?
The side of the case being off is not good, it means that airflow isnt following any direction (Often front to back) and your fans are doing nothing. Since theres no airflow, pockets of hot air can form in the case and will be recycled back into your GPU and CPU.
I'd say its about 20 degrees celcius in my room.. and so are you saying I should put the side on even if its bent? or are you saying its okay that its not on there. The 74 degrees was for my GPU btw, not CPU
what is most important is the temp of your CPU when under 100% load; anything under 74c is acceptable, under 70c is great.
that 5xxx @ 74c is about normal for gaming. if your worried about it you can use after burner to increase the fan speed.
saying it isn't hurting to not have the side on.