Yes,it should be basically the same as my Flash2Advance cart.
It will allow you most certanly to boot your MK2/3, but as a stand alone GBA cartridge it's kind of limited in memory.
Make also sure that the battery inside is still working, otherwise you might end up with Sram problems and not be able to save your games progress on the cart.
But if your intentions are just to use it to boot the MK2/3 then go ahed.
Anyway with flashme v7 you don't need a gba cart to boot the MK, but only the first time basically...