What is the typical frequency drift of an astable 555 circuit over its lifetime?
555 has temperature sensitivity of ~50ppm/C. Delta of 15°F is about 8°C. This gives you 400ppm. 

So your 230kHz clock could be off by 92 Hertz over temperature due to 555 tempco.

If you use capacitors with NP0 dielectric you most likely get very decent temperature and age stability, but this limits you to capacitances &lt;500pF. Vanilla resistors though could have tempco of -500ppm/C, which will shift your frequency by ~920 Hertz.

Aging of the chip itself likely to give much weaker effect. 

So if 1kHz frequency error is ok for you - you are good to go (with NP0 capacitor!). 

PS. Check tempco of your LPF too ;-)