Picked up a couple of Anaheim Stadium postcards a couple months back in a trade of some other teams pocket schedules.
If you looked closely you can see that the photo is of a Rams game.
The Rams enclosed the open stadium in time for the 1980 season and used the stadium from 1980 until they moved to St Louis in 1994.
I noted below some of the indicators that this is a Rams and not an Angels postcard.
The Big A scoreboard in the upper right was also moved from about where the smaller A is above left field (the entire outfield section wasn't there)
The card below shows the batters view prior to the stadium being enclosed.
This isn't a postcard but a promotional card for some Anaheim Stadium artwork.
That's the view I remember when I was kid except we'd usually be in the upper deck where you could see the 57 Freeway and San Bernardino Mountains in the background.