I've never come across an official explanation for the S-badging on the segment cover, which was used on a number of different models. Given the manufacturing date range of those that I've seen, my own theory is that it indicates a De Luxe model. My reasoning is based on mid-'50s Olympia model designations that included -N and -S suffixes; the -N models were standard ("Normal Modell") fitment machines, while the -S variants represented the deluxe versions ("Super-Modell").  

Pretty! I don't have an SM4 but my SM3 has 'De Luxe' in red in the same position. I'm never quite sure what that actually means, to be honest. It's just an SM3 and thus a wonderful thing. I think there are so many variants of various machines - look at all the guises of the Splendids/Socialites/SFs - that any particular thing is going to be more rare than all the others that aren't that particular thing. 

typeset wrote:

Are these machines more rare than other SM4s?

No (see below).

ztyper wrote:

I too have an SM-4 with the little "S" above the segment and I think it's been in every picture of the SM-4 that I've seen. 

It could be argued that the SM4 is a deluxe version of the SM3, and so every machine should be badged as such. However, not every SM4 had the segment cover with the engraved S. I've seen early SM4s with "De Luxe" instead of the S, and later SM4s without any engraving at all. However, these observations are all inconclusive; without knowing the history of each individual model you look at, it can't be positively stated if those other segment covers were original to the machine.
 

More pictures. What is the name of that typeface? Looks very '80s or '90s.


https://lh3.googleusercontent.com/N_ETiqKkIRPTtvXw_4SJasEUew2PbDqCv5z5HAG1OArLhRIEdjYtzs5TAXOf5SDxhu9zvOZHv2bnWw=w1366-h768-rw-no

typeset wrote:

What is the name of that typeface?

http://typewriter.boardhost.com/viewtopic.php?pid=14235#p14235