So... In LR, there is riot armour among many things, I haven't had time by myself yet but I have questions:
Is it basically a non-faction ranger armour?
If so, is it same average DR etc
Does it look the same?

there are variants of it with different colors and DT. The one your referring to is almost the same as the NCR variant except it is non faction.

The Riot Armour has better stats then the Ranger armour in vanilla. There are three versions of the Riot armour, http://www.falloutwiki.com/Riot_gear has some stat bonuses. http://www.falloutwiki.com/Advanced_riot_gear has better DT and different stat bonuses, and http://www.falloutwiki.com/Elite_riot_gear has the second highest DT of and the lowest weight of medium armour. The Advanced and Elite levels only have one set, so look carefully for them.