Grovers have a 10mm diameter, but I don't know the size of the stock tuners on my SX and I don't want or have the tools to drill out the headstock.
Will Grovers fit?
Biu, remove the nut from one and measure, that´s probably the only way you´ll know for sure.
I Personally hold SX in the same High Regard as Stagg, Jay Turser and Harley Benton. Just with the difference that SX seems to change their specs more often. I´ve seen the same axe for the same price, one with "decent" enclosed tuners and one with cheapo covered oned. If it originally had enclosed ones, vour chances are at least better that Grovers will "drop in"