Karin and Ruth are right: samples are sample garments made up to show buyers (from other retailers or manufacturers). They were usually one offs, made as test garments for orders to be taken. Sometimes they weren't very well made, as the style is the thing, so the seams might be unfinished, and they were usually made in small sizes to fit the in-house model (size 6 or 8). The actual orders might have changes: different colours, or changes to the style if the customer wanted it.
I used to work for a London company and managed their sample range, which meant I got first pick at the end of the season and could have what I wanted at cost price.
So the short answer is yes, they have value but that value is variable - like all vintage, depending on quality, condition, style, demand etc.
Nicole