Ooh, a situation where my knowledge of headlamp legislation is useful!
See, 1958 in particular is a special year for U.S. automotive design.
Since 1941, cars designed and sold Stateside were limited to one simple, effective pair of 7" circular lamps… but in 1958? Something new was afoot — now you can have not one, but TWO pairs of (5.75") circular lamps!
Reverse indicators/lamps were not yet required in 1958, but could be had as an additional safety option. (Only required in 1966)
Indicators/turn signals are definitely required by now, but amber is not a required color. In fact, front facing indicators can be white or amber, and rear ones may be red or amber, and can share the housing and/or bulb with the brakelight.
Hide-away headlamps are an option! But those aren’t very common except maybe in concept cars as of '58. Still legal, though. Covering the lamps with a fixed but clear pane was legal until 1968.
Here’s some old but still good references to look at. Perusing the relevant Wikipedia page isn’t a bad idea, either.
And of course, while it may not be specifically headlamp related…
Don’t forget the chrome!