Hello Rick,
The cowling is secured by a cable, not a strap, you can see its end against the black lower portion of the cowling in James' photo. I believe that the black painted strip lies behind the cowling, at the junction with the fuselage. On the kit this area is represented by the thick plastic firewall part.
At least that was my interpretation when I designed the decals. The black strip is provided as a black line decal - probably easier to cut into two pieces for ease of application.
Rowan
PS. It is worth noting that the Vintage Aviator got the tail markings wrong - unusual for them. Compare with the Jasta 6 Lineup photo - it was the same stripe configuration for Jasta 6's Dr.Is.