2002 civic lx keyless entry?

I have an 02 civic lx with power locks and was wondering if i could just buy an oem fob and could program it?

No, used to be a kit available from Honda. Likely discontinued.

I don't think you can, as most Hondas have a driver multiplex module. The key fob would need to be programmed with a factory honda scan tool, and since honda does not release their security software, you'd need to take it to the dealer.