‘‘‘Tis a matter of taste, but a more natural grain suits these best IMO. Smooth grain, or pig would be nice. I have a few faux croc which looks good, but wish they were not faux, as it conflicts with the sincerity of these classic watches. Whatever floats your boat thought. Hirsch makes great ones at good price points, and there are 10 tones of posts about straps here. See if you can find a catalogue pic of your model or year
edit: is it a ‘61? Do let me know if you find a catalogue pic, I’ve been searching but come up empty