We O scale modelers are accustomed to having ladders in just about every box car or reefer kit, whether the prototype had them or not.
For those among us who prize better modeling fidelity, its not a big deal to make the individual grab irons.
The photo I used was a Walthers catalog shot of their 5415 kit.
For me, a kit is a start, not an end product when done.
I've often wondered since my teens in the early 1950's, who built and how long did it take to make all those models used for advertising and catalog photos for the O scale kit producers.
Here are two of my kit built cars The first is a Walthers kit I had from the 1950's. I rebuilt it in1998 to represent I (close, but not exactly) the 'winner' of the 1924 D&H Inter-shop Car Building Contest held at Oneonta NY where I was living at the time. The other is a modified early (warped parts) Chooch USRA box car I built in 2002.
To get hand grabs spaced, I make a brass jig with notches to locate holes to be drilled for them.
I've got three of them now. One always seems work, depending on how tall the car body is.