As per the documentation on overclocking:
When you overclock (i.e. actually change the
gpu_freq tags), the dynamic clock setting will automatically be enabled. This means that the Pi will not run at its maximum frequency unless the load on it is great enough. To disable dynamic clock, the
force_turbo flag can be set to
over_voltage tag applies regardless of the frequency of the
To directly answer your question: No, those two flags alone should not overclock the Pi, the
over_voltage flag will apply, and may bring some more stability to your Pi, but the
force_turbo=1 flag should do nothing.
Here is a direct quote from one of the posts in the thread you linked which seems to support this.
Upon further reflection, I decided to only change one thing at a time. So I only applied the line "over_voltage=6" (based on the link in my previous post). I did NOT apply the force_turbo setting.
My zero's have been stable for almost 2 weeks so far!