This is probably an M-400 A with an M-400 A2 power door, I have seen that often, close to downtown Denver I have seen a couple M-400 A1 FCO's with a new power door, as the power door is much shinier and has the A2 NEMA tag and the rest of the fixture is faded paint and has a lot more scratches on it. Had a notable difference.
On the Lakewood side you see tons of Davits and OVH's. That is what lakewood uses, Davit poles. Everywhere.
On the Wheat Ridge Side there are Truss arms and upsweeps, and a variety of fixtures. Especially the Two OV-25's.
Both are maintained by Xcel Energy, they just use different styles for different cities.