I have both of those in Stock. They come with Thermal conductive tape Pre applied to them.
Remove the backing and place directly on the Driver chips, I Also put them on my Bed, Hotend MOSFETS, If board didn’t already come with some.
Some boards i put them on the SMT32 Chip too.
I can’t say there’s been a notable difference in cooling the CPU, I just feel better about it.
Tall:
Short :
https://3dprintingcanada.com/products/heat-sink-for-a4988-stepper-motor-driver