Here's my 1957 Olympia SM3:
This was a $25 Salvation Army find about five years ago. It was missing its signature silver case; after a few years of searching, I was forced to buy an SM7 case and modify it to fit. I also removed the vinyl wrapping on the ends and refinished the underlying plywood in garnet shellac, to a pretty good effect:
The keycaps on the SM3 are extremely dark brown (almost black.) As far as I can tell they're made of Bakelite, and appear to be double shot with a cream colored plastic which I can't identify (which seems prone to cracking, but this is only an aesthetic issue.)
Interestingly, the keys on this generation of Olympia portable (SM2/3/4) are spring cushioned to take some of the harshness out of bottoming out. It has a noticeable effect on typing. Olympias were some of the better made typewriters in their day, and tended to have features like this.
Other nice features for a portable include a multitude of line spacing settings including the ability to release the line with or without resetting the indentation, a spring loaded paper holder which shows you how many lines are left on the page (accurate if you're using 8.5x11 paper in the US, can be adjusted for smaller sized paper but not larger), line indents for table creation, half spacing for error correction, 6 adjustable tab stops (the sm2 had none, while the SM4 had infinitely adjustable tabs,) key weight selection lever (increases spring tension on the carriage advance rail) and two color ribbon selection. It also, oddly, has an exclamation point (most typewriters from this time omitted this) but you still had to use a lowercase 'l' for the number 1.
My SM3 has the Congress Elite typeface, which I love. It looks quite a bit like a justified Times New Roman, and is one of my favorite things about it:
Overall, this one arrived to me in fair condition, with some paint issues. It was completely out of alignment and required a full servicing to get working.
If you ever come across an Olympia SM2, SM3 or SM4 in the wild for cheap (even in bad cosmetic condition) and are interested in owning a typewriter, I highly suggest buying it and learning to fix it. These Olympias are some of the best feeling typewriters I've experienced, outside of their desktop SG1/3 counterparts, and the later SM9, which has a better feel at the expense of looking very dowdy.
I used to have a fairly extensive typewriter collection, but multiple moves forced me to part with all but this one. It stuck around for a good reason.