I was on active duty from 1958 to1960, do I get extra credit for this

Hi. Yes, but it's not automatic. Social Security adds deemed military wages (DMW) to a person's actual earnings for periods from 1957 through 2001 during which they were on active duty in the U.S. military (https://www.ssa.gov/OP_Home/handbook/handbook.09/handbook-0953.html). From 1968 on, DMWs are credited automatically by Social Security. But, for the years 1957 to 1967, veterans must normally submit proof of their active duty periods to get the DMW credits.

If you're already drawing Social Security retirement benefits, you should have been asked about active military service when you applied for benefits. And, if you submitted proof of your active duty (e.g. form DD-214), DMWs should have been considered when calculating your benefit rate. If you're unsure whether or not you did, you should be able to call Social Security to find out. Social Security can access your records to see if DMWs were added when you applied for benefits.

Best, Jerry