Using my intuition, I would assume the triangle in this simple circuit to be an inverter, but does that look correct? What is this symbol?
It looks like a schmitt trigger inverter like this one (but not this specific one as the pins are different). There should be a Vcc and gnd for this part somewhere else in the schematic.
It's either a Schmitt-trigger inverter or a Schmitt-trigger buffer. It's unclear to me whether the output has a circle or an arrow on it. The hysteresis diagram implies it's an inverter, but that could be wrong.
Edit: as @duskwuff points out, from a functional point of view, it's undoubtedly an inverter. The pin numbers match the SN74LVC1G14 single gate ST inverter, and other similar single gate parts.
Schmitt-trigger gates have input hysteresis which can help in cleaning up slow or somewhat noisy waveforms. In this particular case it does not seem to be doing much in that regard, but it will not do much harm (it will tend to have the RAM outputs fighting each other for a slightly longer during switch transitions than a regular 74LS04 inverter, probably not a big deal).