I had been prepping to fit my heater boxes in replacement of the J-Tubes fitted to my 1956 Oval Beetle. However, after cutting the carpet on the driver side for the vent I pulled back the carpet on the passenger side to discover it had no vents. It looks like there has been a patch welded in maybe to clean up a an old rotten patch...shown in pic:

I need to put the vent back in, the whole channel is solid as a rock but whats the best way to get the vent back in there, easiest, simplest and most cost economical?
Heres a pic of the drivers side footwell of how I need it to look with the vents at the end just before it turns the corner to come around the bulkhead:

Is it possible to buy a segment from anywhere that would match the opposing side and fit my channel just to weld in?