Soooo
you are just going to wash it and baste it to PRESS the pleats.
your not going to change the stitching on the pleats right?
The way I would baste and press it would be to see what the measurement and elements(stripes,colored lines etc. in the tartan design) on EACH individual pleat, from the end of the fell (where it is stitched down) exactly like that down to the end of the pleat.
Baste that then measure and recheck and baste the next.
start at the bottom of the kilt with the basting then after you go all the way across the kilt to the inverted pleat.
Do it all again 3 fingers width down from the fell and add more rows, no more than 4" apart. Baste the apron edges to the inverted pleats or deep pleat or whatever you have there.
I have learned by the "Elsie" method but since it is a military kilt Matt might pipe in and tell you something different if your pleats have been rolled.
No matter what, it will be worth the time it takes to baste it.