It appears so, yes.
Action dice: An elf’s action dice can be used for attacks
or spell checks at any level. At 5th level, an elf can cast
two spells in a single round, the first with a d20 spell
check and the second with a d14; or he can make two attacks,
the first with a d20 attack roll and the second with
a d14; or he may combine an attack with a spell check.
Note that the results of mercurial magic supersede the
action dice, so an elf with a particularly high (or low)
spell check die from mercurial magic uses that result instead
(with his total actions still limited by his level).