MOSFET pinout?

[atlbraves49]

Just want to confirm i have this correctly..

in the following image:

http://www.irf.com/graphics/packages/to220ab.jpg

from left to right, its Gate, Drain, Source ?

it doesnt say on the datasheet
http://www.irf.com/product-info/datasheets/data/irf640n.pdf

[uart]

Yes that's correct, it's shown in the package outline at the end of the datasheet. Note that the heatsink tab is also connected to the drain.