It you look at the different model number choices for 1958 on Marineengine.com
website, you should be about to figure out which model had the electric start.
The first model (15034) listing a starter is a 1961 18 hp. Under the year models 15024, 15025, 15926, and,15927 are listed.024 and 025 no starter but 15926 and15927 model not found. I must be doing something wrong as I can not find a 1958 18 hp electric start.
ME must now have that info anymore for Evinrudes.
A search shows these as electric start in 1958.
I’m guessing the later number is a long shaft, but not sure. https://www.ebay.com/itm/115077033352
best pick is the one with the highest commpression if you can test it …….. and if it has all the parts 58 probably has the lastets improvements built in but… that green Johnson looks nice decal wise…… it seems undamaged and is probably a grandpa motor. (Needs a bit o flove on the paint)