Nice light. The electric utility in the San Diego area, called SDG&E, has lots and lots of those boxy M-250A2 FCOs, they are HPS though. By the way you see there is a single primary wire on the top of the pole, that is called a Single Wire Earth Return (SWER) system. It is adopted in every US state, Mexican state, Canadian province, except California. They somehow never adopted the SWER/shared neutral system, so where ever you go in California, there's always a minimum of two primary lines on the top of the utility pole.
Yeah the transformer is either a replacement or a new one. NGrid has been replacing transformers over the past five years or so. Normally they replace the pole though since lots of poles around here like this one are well past their prime. I would love to get one of these boxy M-250A2s. They're just really cool looking lights. They play a good role in my childhood too since the M-250A2 FCOs in my neighborhood are the only "white glow" lights in that area. Around here we have these boxy ones and then we have the ones that have the more rounded top (but still have the flat front). We don't have any of the current M-250A2s here with the rounded nose and top though. That's interesting about the primaries. So California uses an older system?