Since the resistors and capacitors have a typical +/- 20% variation, the oscillator must be capable of adjusting its value in some kind of a feed-back loop.
What you could hypothesize is some kind of circuit that translates the frequency domain into a DC value of some sort that can be compared to a more accurate reference.
To my best knowledge, the best bandgap I every saw was +/- 6% over process, temperature, mismatch and 5-sigma, untrimmed. The circuit that will translate the frequency to the accurate reference will add additional mismatch.
Therefore, since there is no +/- 5% untrimmed reference to begin with and we have to leave some error for the theoretical "translation" circuit, we can conclude that it is impossible to generate a +/- 5% oscillator untrimmed on a typical IC process.
In practice, even if we could generate some kind of an accurate reference (i.e. external voltage), there is no accurate way of changing a frequency into a DC value. If you create a rectifier type circuit that has a filter at the front, you will get a DC value that is a function of the frequency at the point where the filter is rolling off. However, the filter varies all over with the C and R's, and the diode's Vt varies with temperature and process. I have never come across an untrimmed circuit that can accurately translate a frequency to a DC value.
Greg