Exclamation mark on the order detail and in the part out details would be very
handy if a part had a known variant. We do our best to match the specific mold
customer ordered but sometimes incorrect variant ends up in the storage bin of
another variant due to errors in the catalog or with sorting error. If you catch
your error at the inventory level it's still not problematic but once someone
orders a variant more than you have it's almost always more involving with
exchanging messages with customer.
Such exclamation mark on the part out details would increase the chances that
someone submit an alternative part catalog change request. (I don't think
it would be done on the legacy system but that addition of alternative part may
be simplified by just asking the user which part was included in the set instead
of what was shown in the catalog)
In the order detail page it would serve the seller to be extra cautious about
the variant, at least there would be higher chance that the situation is assessed
before the order is in the hands of the customer.