This one also looks different than other Model 25's. Which generation is this? Is it one of the first Model 25's or one of the last?

Looks more like the last to me (before they started having nema tags on them like some of the later ones from the late 70s early 80s do in some of my other pictures of this kind) 'cause the earlier version would have a dark silvery paint job to it like what I've seen in South Boston.

Actually this is the FIRST generation Model 25, one of the later versions as this has a grey finish. The hinges show as a first generation. The last generation Model 25 had hinges just like the Model 125's or 115's you see today. And the last generation also has the Leveling-pad on the bottom, the first generations didn't.

I saw one silvery-finish HPS Model 25 (first generation) in Denver in a neighborhood, what a surprise to find a first generation.

I think David was saying this was one of the last 25s made before the newer one with the bubble level pad. This ISN'T the first style 25 because this isn't silver and the American Electric logo isn't on the door like the very early ones are.