Yes, it is a straight drop in. Although, I would remove the white casing of the TIR optic before installation. I have had a few times where the white casing fit too snug within the flashlight housing and I ended up spinning the led MCPCB and shorting some wires while installing the pill. Never had that problem with the white TIR casing removed.

Also, I prefer to leave in the lens and o-ring for waterproofing. Just replace the reflector with the TIR.