John,
It is a chrome bumper car built in 12/73 so it just "missed" the Sabrina bumpers that were added after 1/1/74. It was on the road when I bought it last summer, now perched on jackstands in my garage while I replace the doglegs and lower front fenders. Luckily, I was able to patch the outer rockers. The inner membrane, castle rail and sills are all solid. I caught it at a good time.
I have been following your project on The MGB Experience. Keep us posted!
Jack