Looks very similar to mine.
If it was sold as a cased set and you have the original case that might be helpful for dating. Starrett never provided useful date of manufacture labels on their tools. They seem to have been putting naked, uncased, things in the same style of red cardboard box with easi-peel labels for longer than I've been alive.
Mine was said to be 1950's vintage. The case is black dimpled / scaled leatherette covered wood with the top and bottom tapered slightly where they meet the sides. Unhanded slide tiype catches.
Over the years Starrett have used a variety of box styles. I believe that the combination square cases generally followed the current house style for sets of equipment and large micrometers or verniers.
Prewar tended to be boxwood or similar with either slide out tops or hinged opening ones.
There was a post war (I think) period when nicely polished hardwood cases with matched cut-outs for the components in the lower half were the norm. Later came nice red leatherette coverd hinged cases with spring closure and chrome embellishments around the edges of base and lid. Foam inserts with recesses for the various parts. Unfortunately the foam disintegrates after 20 – 30 years.
I think matt black paint came in during the early 2000 s.
Clive