Mike, my impression is that they were quite limited. From a practical standpoint, the "sponge-like" thickness of the material would have absorbed the "juices" of items carried in a haversack, readily rinsed out of common cotton or linen. As with other items such as distinctive, individually obtained insignia ("PX purchases" to a later generation) and non-issue equipment, a re-enactment unit might tolerate a few examples, but such items so readily get out of hand as others want to emulate. If re-enactment is involved, you might want to check with Authentic Campaigners at their web site herewith, and see prevailing attitudes.
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