Yes it does, log into the game and try the following macro:
Code:
#showtooltip
/use [mod][combat]Hearthstone;Attack;<Mountname>
Just some random example I thought of in 2 seconds though. And the last time I check(and used) the "all parameters in the beginning"-macro was 2.5 weeks ago.
And to prove that macro explain-o-matic is not always right:
/use Attack? In the tooltip when hovering over the ?: The /use command takes items. Attack was recognized as a spell. Did you mean to use a command like /cast instead?