Electronic configuration of excited states of iron
The electronic configurations of the excited states of neutral iron are listed on this NIST Database page:


3d64s2 — a 5D — ground state
3d7(4F)4s1 — a 5F — 6928.268 cm–1
3d7(4F)4s1 — a 3F — 11976.238 cm–1
3d7(4P)4s1 — a 5P — 17550.180 cm–1
3d64s2 — a 3P — 18378.185 cm–1
3d6(5D)4s14p1(3P) — z 7D0 — 19350.892 cm–1


The reference give for this data is: G. Nave, S. Johansson, R. C. M. Learner, A. P. Thorne, and J. W. Brault, Astrophys. J. Suppl. Ser. 94, 221 (1994).



So, while in general predicting electronic configurations for excited states is a tricky business, you are right: the first excited electronic configuration is to “promote” one 4s electron into the 3d orbitals. And the second excited state configuration (regardless of the different spectroscopic terms and sublevels) is to promote the 4s electron into 4p.