Was this before or after Lincoln locked up all the ones in favor of it?
Marylanders served in the Union Army about two-to-one over the Confederate army.
You suggest a lot of significance with a bit of data like this, but was not Maryland occupied by Federal armies at the time? Wasn't it more likely that the men of Maryland would be pressed into service by the Union and only Volunteers who could leave the state would join the Confederacy?
It was a lot easier to get into the Union army from Maryland than it was to get into the Confederate army if you were in Maryland.
“Was this before or after Lincoln locked up all the ones in favor of it?”
The Maryland legislature voted 53-13 against secession on April 29. Butler and a 1,000 troops didn’t enter Baltimore until May 13th. So the answer to your question is that Maryland voted overwhelmingly against secession before Martial law was imposed and pro Confederate officials arrested.
During the Civil War, 26 infantry regiments (6 USCT), 4 cavalry regiments, 1 heavy artillery regiment and 6 artillery batteries from Maryland served in the Union Army.
Confederate Maryland units consisted of 2 infantry regiments, 2 cavalry regiments and 4 batteries of artillery.
When Lee invaded Maryland in 1862, his army brought along 2000 extra rifle muskets for the purpose of being issued to the Maryland recruits that would flock the Confederate flag.
When Lee’s Army retreated out of Maryland, they brought back all 2000 rifle muskets, unissued.