You can view the slice timing with

3dAttribute TAXIS_OFFSETS dset+orig

Slice timing can be corrected with an alternate time pattern than the one stored in the header with
3dTshift -tpattern ... dset+orig

where the tpattern option can be specified per the help for 3dTshift
-tpattern ttt = use 'ttt' as the slice time pattern, rather
than the pattern in the input dataset header;
'ttt' can have any of the values that would
go in the 'tpattern' input to to3d, described below:

alt+z = altplus = alternating in the plus direction
alt+z2 = alternating, starting at slice #1 instead of #0
alt-z = altminus = alternating in the minus direction
alt-z2 = alternating, starting at slice #nz-2 instead of #nz-1
seq+z = seqplus = sequential in the plus direction
seq-z = seqminus = sequential in the minus direction
@filename = read temporal offsets from 'filename'

Alternatively, you can reset the attribute in the header with 3drefit

3drefit -atrfloat TAXIS_OFFSETS "..." dset+orig

with the correct time offsets inside the quotes following "TAXIS_OFFSETS"

One other way is to reread the .BRIK file or original DICOM files with to3d and specify the correct tpattern and all the other specifications for the data.