Short answer is No.

At the best case, barrel could be ported in the grooves of the barrel twist, but your still paying with interrupted lands of the rifling that the thin waxed/plated bullet has to move through, and it not going to end up in your favor.  Also, there is the option of just back boring the barrel deeper from the muzzle end, but may end up with a baffle strike instead.

So would be best just forgo the porting, and spend the money on something like CCI standard velocity ammo now isntead.  
22lr ammo is becoming available again, and although the prices are still somewhat high, they will soon drop down again instead.

The first  gen system (ports top and bottom about a inch from the  chamber) did not allow your super sonic ammo from becoming super sonic in the first place.
Hence even mini mags would stay subsonic in the unit.  The glitch though, it fouled the hell of of the treads/baffle to tube if you did not stay on top of cleaning the can (very few hundred rounds).

The second design pushed the ports more forward (about 2" off the chamber), but this caused some super sonic ammo to stay super sonic isntead (sounds like you have this gen can).  But since the forward ports still causing fouling problems with threads and  sleeves to baffle stack (if you where not cleaning the can frequently), Gemtech would replace the barrel with one none ported on request instead.  




So if you want the can to keep  all  supersonic ammo subsonic, then request Gemtech to install a first gen ported barrel on the unit that is proven to work for that.     Just remember to keep the unit clean, and silicone spray is going to be your lube of choice to give the can and threads a good lubing before you put the shroud back on your more frequent cleanings (every few hundred rounds).  The no ports is still an option, but your going to loose any abilities that it may had with keeping some value brand super sonic ammo sub sonic isntead.

As for accuracy, keep in mind that is does not have a Lilja, Broughton, Hart, Shilen, Border barrel with Benz chamber and almost a press fit to the receiver that would be a proven design to keep the barrel/rig Sub MOA at 100 yards, so your still back on luck of the draw of what ever their none ported production barrel is going to group if you go that way isntead.

Bottom line, you have had the unit for a while now, and should know what roll you want it's to fill (hopefully the keeping the ammo subsonic thing since it does have a production barrel on it), and would have a chat with them about turning the unit back into a first gen isntead.  Here it had it cleaning problems, but at least kept all the super sonic ammo sub sonic instead.