Motherboards are made in production runs.
Sometimes they make changes in the motherboards because of small
design changes, component availability changes because they can't
get a part, or another part is cheaper.
Sony instead of using Revision 1 and Revision 2 numbering system
labels their board with a TA- series numbering system.
When you are looking at a motherboard to make mods and someone
says you have a TA-079 motherboard then the pictures from one
079 motherboard are the same as all other 079 motherboards.
Also the external boards like the wifi board has to match to the version
motherboard you have so a TA-079 motherboard has to go with a
TA-079 wifi board.
That way everything works together.
Also you will see some talk about a new motherboard that can not
run custom firmware yet.