Hello
I have a 16 pin IC to install, but the top markings are totally impossible to see.
I cannot identify any dot for pin one.
Underneath however, one corner is cut at 45 degrees...... am I right in assuming this is pin 1? (well, the corner that starts at pin 1).
h
that's an assumption that would be consistent with typical notched corners (to indicate where pin 1 lives) and pins are numbered around a chip counter-clockwise when looking at the top (so reversed if you are looking at the bottom)
it still remains an assumption though.... 
Post the type number of the IC. Your picture shows that it is a 24-pin IC.
Look at the datasheet for the chip, It will tell you!
It doesn't.... I checked. Shows a dot, but that has long since gone.
The dot is for people, visual, identification of pin 1. The cut corner is for machine identification of pin 1, pick-and-place machine.
I thought P&P machines are preprogrammed with the orientation of the device, since it comes from an oriented reel or tray. The camera systems in P&P machines are used for high accuracy in placing (and detecting a dropped component) - I guess they could also verify pinout, but I doubt that's needed since once set up its going to be consistent.
The pinout numbering of ICs comes from the original standard for valves, clockwise from 1 when viewed from the underside (the natural orientation for wiring up a valve base, or soldering a through-hole PCB). Clockwise was chosen as more natural for people.
These days of SMT the top view is the natural one, so the less natural CCW direction is a legacy thing.
There are a few ICs that come in alternate packages with a heat slug either on top or underneath - basically the same package with the pins bent the other way, so that the numbering goes the "wrong way" on one version of the package!
So for such chips (heat slug on top), always check the datasheet to be sure.
This is true, but reels and trays have mistakes, Our My-Data machines always checked orientation with a pin BEFORE the device was removed from a tray/reel pocket.
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