Do these mount at the original factory location without modification?

Yes, these mount at factory rocker and bumper mounting points — no drilling or extra modification needed. Line them up with the OEM anchor holes and you're set.

Are the bulbs already in these, or do I need to source them separately?

Red bulbs come pre-installed in both units. You don't need to buy or install anything else on the bulb side.

Will the crystal clear lens let me see the red bulb light, or does it look too clear?

The crystal clear lens is designed to show the red glow when the bulb is lit — it's not frosted or opaque. Brightness and visibility are factory-standard.