That's interesting, I'd never noticed the wording of the warranty info on them before now. I doubt that there would be an issue getting warranty work done even lacking the original receipt and no matter how many hands it had passed through. The knives were the same as the regular series, they were just marked and marketed in a different manner. If I remember right, they also sold other, non-cutting items such as tool bags under their "Workman" name, so the limited warranty may have applied to those items more than the knives.
Here's something posted by CJ Buck a few years back about them:
CJ Buck
Workman was a series developed to try to get knives merchandised in two different locations in a store. There was a separate catalog and sell sheets. We were going to put separate rep groups selling to the tool/hardware buyer as well as the sporting goods buyer.
We tried to make some unique products as well as take some existing product and create a "family" that could go into the tool/hardware section of a store as well as be more appropriate for the then new home center stores.
It was not successful enough to cover the overhead and inventory required and discarded.
I will ask Joe if he has any of those workman catalogs
CJ Buck
Buck Knives, Inc.
AKTI Member #PR00003