Inqquired to a guy on CL who had a bunch of random GM (or gm) bumpers/sheetmetal and he said he had this. I think he may be local to me (I asked) and if so I'm happy to try and arrange getting it & bringing to the Nationals or shipping. He also said he'd be @ spring Carlisle. https://baltimore.craigslist.org/pts/d/abingdon-new-nos-gm-bumpers-fenders/7302502011.html
There's no pics of it - I can find the link again if someone is interested or they can search up "Skylark" on Baltimore CL.
I figured you couldn't get one re-chromed for that plus so rare to any significant '73-4 NOS parts. If I had the spare cash, I'd grab it in the hopes of getting a car for it someday. The guy did get back to me and is relatively local (40 min + tunnell tolls) so I'm happy to assist. Fixed the link too.