Only if you go outside state lines to do the modification.
"Illegal to purchase, sell or manufacture magazines with a capacity of greater than 10 rounds within Maryland. However, possession of magazines greater than 10 rounds is legal if purchased out of state. These may not, however, be...
Just a thought if you want to stick with the MK II - I installed a Majestic Arms speed strip kit which lets pull the lock pin out with an allen wrench, can always be reversed if you decide to sell later and want it back to original format. I have a MK III but it also apparently works for the Mk...
I would think you would have a better chance making an argument for this one to be legal since technically the parts are not interchangeable with a standard Springfield M1A; just learn to shoot left handed I guess...
Also, they don't allow steel cased ammo. They run a magnet over your ammo to check. Aluminum case is ok or at least I have not seen anyone get kicked out for using it there.