My dad was an artist (painting, sculpture, stonecutting, illustration). He forayed into many media during his lifetime. One of his experiments was plating sculptures. A few examples were sculptures made of wax that was, then, plated. The process did not melt the wax and it was easy to dent the plating as the wax couldn't resist the denting forces. Seeing these items established in me an awareness of the capabilities of plating.
Then there are all of those bronze baby shoes. One of my favorite plated soft items was plated polystyrene (from scaled plastic models).
I raise the point to suggest that lead or even bondo can be plated over. The matter of doing such a thing then becomes more of an ethical issue than a technical one.
Like all bondo work it is a inexpensive work around to solve a metal imperfection. Hopefully members on the list subscribe to the notion of disclosure of such practices if you are selling a frame repaired/finished this way.
Todd Teachout
Hercules, CA