Horton IX V3 Manufacturer Markings

The Smithsonian National Air and Space Museum is beginning a detailed survey of it Horton IX V3 in preparation for preservation / restoration activity.
Printed markings have been found on the unpainted plywood formed into the leading edge of the fuselage left center section. Photos of the markings are attached. They appear to have been applied by a roller device. Salient elements of the markings are 1. Concentric circles, divided into quadrants with faint lettering between the circles; 2. a large "38"; 3. a "4" followed by what could be a "3".
We are attempting to identify the marking; determine if it was applied during the material acceptance, the plywood manufacturing process or the airframe manufacturing process. If applied during the plywood manufacturing process, then we can identify the adhesive and better stabilize the artifact during preservation / restoration activity. We cannot assume the adhesive was from the Goldschmitt Tego-Film Wolldau plant. We cannot determine if the artifact was assembled in the Horton workshops or the Gotha Works.
The issue is somewhat time sensitive. Any assistance would be appreciated.
Thank you.
GWC