Would you say I have a drain on my battery or is this normal?

Last night around 230am I put a multimeter on my battery and it read 12.9 volts.

This afternoon, around 3pm, it read 12.6 volts.

Would this voltage drop be considered normal or should I investigate a drain on my system?

Likely normal.

A standard lead acid battery will have various voltages at various charge levels at various ambient temperatures:

http://www.buchanan1.net/lead_acid.shtml

Not unusual.

Are you experiencing any symptoms that made you suspect a drain?

If you are having troubles, first thing would be to "load test" the battery to be sure it is up to snuff before looking elsewhere.