Yes, it's correct for the model. Interesting because I had looked at many photos of them before and you don't always notice the lights.
The assumption is that with 4 marker lights, they'd have 2 red and 2 white in each direction They had a single red as did the 141 and 071 when delivered (although they came with 2+1 light clusters, not 2+2).
Unlike the 141, 181s and big Gms that followed the 121s were delivered with 2+2 clusters. Here's one being unboxed
You can clearly see that three of the markers are white in 122s
I think a lot of switching took place as needed to keep the close operative 130 with 3marker light
....and 130 with 1+3 prior to that. It may be possible that spare from 141/181 were available more readily as time elapsed that for the 121 as the 2+1 cluster seem to be more common later in several locos including 123, 124, 128, 130 132 and probably more
Al that said, what was lit is a bit of a guess and needs to come definitively from someone closer to the railways the me, I se nor more than 2 white lights lit here